Oxidative Stress in the Newborn Period: Useful Biomarkers in the Clinical Setting

Neuroglobin overexpression in cerebellar neurons of Harlequin mice improves mitochondrial homeostasis and reduces ataxic behavior

Neuroglobin, a member of the globin superfamily, is abundant in the brain, retina, and cerebellum of mammals and localizes to mitochondria. The protein exhibits neuroprotective capacities by participating in electron transfer, oxygen supply, and protecting against oxidative stress. Our objective was to determine whether neuroglobin overexpression can be used to treat neurological disorders. We chose Harlequin mice, which harbor a retroviral insertion in the first intron of the apoptosis-inducing factor gene resulting in the depletion of the corresponding protein essential for mitochondrial biogenesis. Consequently, Harlequin mice display degeneration of the cerebellum and suffer from progressive blindness and ataxia. Cerebellar ataxia begins in Harlequin mice at the age of 4 months and is characterized by neuronal cell disappearance, bioenergetics failure, and motor and cognitive impairments, which aggravated with aging. Mice aged 2 months received adeno-associated viral vectors harboring the coding sequence of neuroglobin or apoptosis-inducing factor in both cerebellar hemispheres. Six months later, Harlequin mice exhibited substantial improvements in motor and cognitive skills; probably linked to the preservation of respiratory chain function, Purkinje cell numbers and connectivity. Thus, without sharing functional properties with apoptosis-inducing factor, neuroglobin was efficient in reducing ataxia in Harlequin mice.

Oxygen in the neonatal ICU: a complicated history and where are we now?

Despite major advances in neonatal care, oxygen remains the most commonly used medication in the neonatal intensive care unit (NICU). Supplemental oxygen can be life-saving for term and preterm neonates in the resuscitation period and beyond, however use of oxygen in the neonatal period must be judicious as there can be toxic effects. Newborns experience substantial hemodynamic changes at birth, rapid energy consumption, and decreased antioxidant capacity, which requires a delicate balance of sufficient oxygen while mitigating reactive oxygen species causing oxidative stress. In this review, we will discuss the physiology of neonates in relation to hypoxia and hyperoxic injury, the history of supplemental oxygen in the delivery room and beyond, supporting clinical research guiding trends for oxygen therapy in neonatal care, current practices, and future directions.

A Comprehensive Review of Bovine Colostrum Components and Selected Aspects Regarding Their Impact on Neonatal Calf Physiology

Colostrum contains macro- and micronutrients necessary to meet the nutritional and energy requirements of the neonatal calf, bioactive components that intervene in several physiological aspects, and cells and microorganisms that modulate the calf's immune system and gut microbiome. Colostrum is sometimes mistaken as transition milk, which, although more nutritive than whole milk, has a distinct biochemical composition. Furthermore, most research about colostrum quality and colostrum management focuses on the transfer of maternal IgG to the newborn calf. The remaining components of colostrum and transition milk have not received the same attention, despite their importance to the newborn animal. In this narrative review, a large body of literature on the components of bovine colostrum was reviewed. The variability of these components was summarized, emphasizing specific components that warrant deeper exploration. In addition, the effects of each component present in colostrum and transition milk on several key physiological aspects of the newborn calf are discussed.

The effect of fetal hypoxia on myeloperoxidase levels in cord blood: a prospective study

BACKGROUND

We aimed to compare myeloperoxidase (MPO) levels in cord blood samples of mothers with and without perinatal hypoxia, since fetal hypoxia results in decreased pH, base excess, and an increase in pCO2 and lactate levels.

METHODS

We enrolled 42 pregnant women to this cross-sectional analytic study if they had met following criteria: uneventful gestational follow-ups, no known chronic or pregnancy-associated diseases, a BMI of <29.9, a singleton pregnancy, those with pregnancy over 34 weeks. The exclusion criteria for the study and control groups were as follows: presence of multiple pregnancies, fetal abnormality, any disease diagnosed before or during antenatal follow-up e.g., diabetes, hypertension, thyroid dysfunction, uncontrolled endocrine disease or abnormal kidney function, autoimmune disease, chronic inflammatory diseases, IUGR, preeclampsia), maternal age below 18 or above 35, intrauterine exitus, pregnancy with assisted reproductive technique, alcohol or smoking addiction, and any chronic drug use. The subjects were 1:1 randomized to either hypoxic newborns (N.=21) and those in the control group (N.=21) and their myeloperoxidase levels were measured from cord blood samples. Results were expressed as U/L. Patient data regarding age, gestation, parity, birth weight, birth length, APGAR scores, and neonatal complications were collected. All the women signed written informed consent forms and accepted verbal consent before being included in the study.

RESULTS

The mean age of the study population was 26.9±5.3 years. The mean BMI was 28.3±3.5 kg/m2. For the hypoxic group, 21 newborns with cord blood below 7.25 were included in the study group. The bloods with pH above 7.25 formed the control group. Mean pH and five (5) minute APGAR scores were found to be significantly lower in the study group, while base excess (BE) was found to be significantly higher. In this study, we compared the MPO levels of hypoxic newborns and those in the control group, and we did not find a significant difference between the two groups (P=0.147). Pearson Correlation Analysis is at -0.566 with P value (0.008) showing significant negative correlation between MPO and pH in the study group.

CONCLUSIONS

We found that MPO values are negatively correlated with cord blood pH among newborns diagnosed with fetal hypoxia.

The Urinary Metabolome of Newborns with Perinatal Complications

Maternal pathological conditions such as infections and chronic diseases, along with unexpected events during labor, can lead to life-threatening perinatal outcomes. These outcomes can have irreversible consequences throughout an individual's entire life. Urinary metabolomics can provide valuable insights into early physiological adaptations in healthy newborns, as well as metabolic disturbances in premature infants or infants with birth complications. In the present study, we measured 180 metabolites and metabolite ratios in the urine of 13 healthy (hospital-discharged) and 38 critically ill newborns (admitted to the neonatal intensive care unit (NICU)). We used an in-house-developed targeted tandem mass spectrometry (MS/MS)-based metabolomic assay (TMIC Mega) combining liquid chromatography (LC-MS/MS) and flow injection analysis (FIA-MS/MS) to quantitatively analyze up to 26 classes of compounds. Average urinary concentrations (and ranges) for 167 different metabolites from 38 critically ill NICU newborns during their first 24 h of life were determined. Similar sets of urinary values were determined for the 13 healthy newborns. These reference data have been uploaded to the Human Metabolome Database. Urinary concentrations and ranges of 37 metabolites are reported for the first time for newborns. Significant differences were found in the urinary levels of 44 metabolites between healthy newborns and those admitted at the NICU. Metabolites such as acylcarnitines, amino acids and derivatives, biogenic amines, sugars, and organic acids are dysregulated in newborns with bronchopulmonary dysplasia (BPD), asphyxia, or newborns exposed to SARS-CoV-2 during the intrauterine period. Urine can serve as a valuable source of information for understanding metabolic alterations associated with life-threatening perinatal outcomes.

Femoral Occlusion during Neonatal Cardiopulmonary Resuscitation Improves Outcomes in an Ovine Model of Perinatal Cardiac Arrest

BACKGROUND

The goal of chest compressions during neonatal resuscitation is to increase cerebral and coronary blood flow leading to the return of spontaneous circulation (ROSC). During chest compressions, bilateral femoral occlusion may increase afterload and promote carotid and coronary flow, an effect similar to epinephrine. Our objectives were to determine the impact of bilateral femoral occlusion during chest compressions on the incidence and timing of ROSC and hemodynamics.

METHODOLOGY

In this randomized study, 19 term fetal lambs in cardiac arrest were resuscitated based on the Neonatal Resuscitation Program guidelines and randomized into two groups: femoral occlusion or controls. Bilateral femoral arteries were occluded by applying pressure using two fingers during chest compressions.

RESULTS

Seventy percent (7/10) of the lambs in the femoral occlusion group achieved ROSC in 5 ± 2 min and three lambs (30%) did not receive epinephrine. ROSC was achieved in 44% (4/9) of the controls in 13 ± 6 min and all lambs received epinephrine. The femoral occlusion group had higher diastolic blood pressures, carotid and coronary blood flow.

CONCLUSION

Femoral occlusion resulted in faster and higher incidence of ROSC, most likely due to attaining increased diastolic pressures, coronary and carotid flow. This is a low-tech intervention that can be easily adapted in resource limited settings, with the potential to improve survival and neurodevelopmental outcomes.

Oxidative Stress Levels and Dynamic Thiol-Disulfide Balance in Preterm Newborns with Bronchopulmonary Dysplasia

OBJECTIVE

The aim of this study was to assess the oxidative stress (OS) levels and dynamic thiol-disulfide balance in preterm newborns with bronchopulmonary dysplasia (BPD).

METHODS

This prospective study included newborns separated into 2 groups, those with BPD (case) or without BPD (control). The 2 groups were compared by clinical and laboratory findings. The OS parameters total oxidant status (TOS), total antioxidant status (TAS), OS index (OSI), native thiol (NT), and total thiol were measured within the first day after birth. Oxygen requirements were measured using the fraction of inspired oxygen (FIO2) recorded in the first hour after birth/admission and the average FIO2 within 28 days of the birth.

RESULTS

Infants diagnosed with BPD had a significantly lower gestational age and birth weight and a lower 5-min Apgar score (P < .05). Infants with BPD also had a higher rate of respiratory distress syndrome, rate of use of surfactant therapy, duration of ventilation therapy, and duration of hospital stay compared with control (P = .001, P = .001, P = .001, and P = .001, respectively). Plasma TAS and NT levels of newborns with BPD were significantly lower than newborns without BPD (P < .05). In the BPD group, plasma TOS and OSI levels were significantly higher than in the control group.

CONCLUSION

We found that OS was increased in newborns with BPD. The clinical significance of this study will provide the clinician with a different perspective on BPD by determining the dynamic thiol disulfide balance.

Does Perinatal Intermittent Hypoxia Affect Cerebrovascular Network Development?

Perinatal hypoxia is an inadequate delivery of oxygen to the fetus in the period immediately before, during, or after the birth process. The most frequent form of hypoxia occurring in human development is chronic intermittent hypoxia (CIH) due to sleep-disordered breathing (apnea) or bradycardia events. CIH incidence is particularly high with premature infants. During CIH, repetitive cycles of hypoxia and reoxygenation initiate oxidative stress and inflammatory cascades in the brain. A dense microvascular network of arterioles, capillaries, and venules is required to support the constant metabolic demands of the adult brain. The development and refinement of this microvasculature is orchestrated throughout gestation and in the initial weeks after birth, at a critical juncture when CIH can occur. There is little knowledge on how CIH affects the development of the cerebrovasculature. However, since CIH (and its treatments) can cause profound abnormalities in tissue oxygen content and neural activity, there is reason to believe that it can induce lasting abnormalities in vascular structure and function at the microvascular level contributing to neurodevelopmental disorders. This mini-review discusses the hypothesis that CIH induces a positive feedback loop to perpetuate metabolic insufficiency through derailment of normal cerebrovascular development, leading to long-term deficiencies in cerebrovascular function.

Inflammatory Processes in Alzheimer's Disease-Pathomechanism, Diagnosis and Treatment: A Review

Alzheimer's disease is one of the most commonly diagnosed cases of senile dementia in the world. It is an incurable process, most often leading to death. This disease is multifactorial, and one factor of this is inflammation. Numerous mediators secreted by inflammatory cells can cause neuronal degeneration. Neuritis may coexist with other mechanisms of Alzheimer's disease, contributing to disease progression, and may also directly underlie AD. Although much has been established about the inflammatory processes in the pathogenesis of AD, many aspects remain unexplained. The work is devoted in particular to the pathomechanism of inflammation and its role in diagnosis and treatment. An in-depth and detailed understanding of the pathomechanism of neuroinflammation in Alzheimer's disease may help in the development of diagnostic methods for early diagnosis and may contribute to the development of new therapeutic strategies for the disease.

Oxygen for the Newborn: Friend or Foe?

Oxygen supplementation is widely used in neonatal care, however, it can also cause toxic effects if not used properly. Therefore, it appears crucial to find a balance in oxygen administration to avoid damage as a consequence of its insufficient or excessive use. Oxygen toxicity is mainly due to the production of oxygen radicals, molecules normally produced in humans and involved in a myriad of physiological reactions. In the neonatal period, an imbalance between oxidants and antioxidant defenses, the so-called oxidative stress, might occur, causing severe pathological consequences. In this review, we focus on the mechanisms of the production of oxygen radicals and their physiological functions in determining a set of diseases grouped together as "free radical diseases in the neonate". In addition, we describe the evolution of the oxygenation target recommendations during neonatal resuscitation and post-stabilization phases with the aim to define the best oxygen administration according to the newest evidence.

Clinical significance of correlation between persistent pulmonary hypertension and 8-hydroxy-2-desoxyguanosine level in premature newborns

BACKGROUND: Persistent pulmonary hypertension is a problem that leads to high morbidity and mortality in preterm infants. In clinical studies, oxidative stress (OS) contributes to the development of pulmonary hypertension (PH). The most specific biomarker of OS in preterm infants is urinary 8-hydroxy-2-deoxyguanosine (8-OHdG). The aim of the study was to determine the clinical correlation between the value of 8-OHdG and the level of a mean pressure in the pulmonary artery (mPAP) in premature infants with respiratory distress syndrome (RDS) and asphyxia in the early neonatal period. METHODS: Determination of the urinary 8-OHdG value and PH in 96 premature infants born at gestational age of 26–32 weeks on the 1st and the 3rd–5th days of life in two groups: group I –52 children with respiratory distress syndrome; II –44 children with RDS associated with perinatal asphyxia. RESULTS: The 2nd group of children had higher average mPAP level, mmHg, both in the 1st and in the 3rd–5th day of life compared with the 1st group. The value of the urinary 8-OHdG correlated with the manifestation of PH that required prolonged respiratory support in group II. CONCLUSION: Perinatal asphyxia in preterm infants with RDS on the 1st day of life complicates the course of PH, as indicated by a higher level of the urinary 8-OHdG and correlated to mPAP. Gender characteristics of the dynamics of 8-OHdG levels in children with perinatal pathology reveal reduced adaptability and reactivity of boys to OS at birth.

The safety of pediatric use of paracetamol (acetaminophen): a narrative review of direct and indirect evidence

Paracetamol (acetaminophen) use during pregnancy and early childhood was accepted as safe in the 1970s, but is now a subject of considerable concern. Careful analysis shows that initial acceptance of the drug was based on the false assumption that drug interactions in babies and adults are the same, and on a complete absence of knowledge regarding the impact of the drug on brain development. At least fourteen epidemiological studies now indicate that prenatal exposure to paracetamol is associated with neurodevelopmental problems. Based on these studies, it can be concluded that prenatal exposure to paracetamol causes statistically significant risks of developmental delays, attention deficit hyperactivity disorder, and a subtype of autism spectrum disorder (ASD) associated with hyperkinetic behavior. In contrast, data regarding postnatal exposure to paracetamol are limited, and several factors impede a classic multivariate analysis of epidemiologic data to resolve the issue. However, circumstantial evidence regarding postnatal exposure to the drug is abundant, and includes at least three otherwise unexplained temporal relationships, data from laboratory animal studies, several miscellaneous and otherwise unexplained correlations, and a lack of alternative suspects that fit the evidence-derived profile. Based on this evidence, it can be concluded without any reasonable doubt that oxidative stress puts some babies and children at risk of paracetamol-induced neurodevelopmental injury, and that postnatal exposure to paracetamol in those susceptible babies and children is responsible for many if not most cases of ASD.

Treatments and therapeutic protocols for the recovery of an asphyxiated new-born: A review of pre-clinical and clinical studies in human neonates and in different animal models

The objective of this review is to ascertain the advantages and disadvantages of several treatments and therapeutic protocols that have been used for the prevention and treatment of perinatal asphyxia in human neonates and in different animal models. Perinatal asphyxia is one of the main causes of mortality worldwide and is an important factor in triggering physio-metabolic disorders that result in serious neurological consequences and learning disorders not only in human foetuses and neonates, but also in animals. In recent years, the search for new pharmacological protocols to prevent and reverse physio-metabolic disorders and brain damage derived from perinatal asphyxia has been and continues to be the subject of intense research. Currently, within these pharmacological protocols, therapeutic strategies have been evaluated that use respiratory and hormonal stimulants, as well as hypothermic therapies in combination with other putative neuroprotective agents. Similarly, energy supplements have been evaluated with the objective of preventing perinatal asphyxia and treating new-borns with this condition, and to decrease the incidence of neonatal and foetal deaths associated with it. However, despite these promising advances, this pathology has persisted, since the administration of these therapies in low doses may not exert a neuroprotective effect or, in high doses, can trigger adverse effects (such as reduced cardiac contractility, reduced cerebral blood flow, poor perfusion, sympathetic and neuroendocrine stimulation, and increased blood viscosity) in human foetuses and neonates as well as in different animal models (rats, piglets, sheep and rabbits). Therefore, it is important to determine the minimum effective dose with which these therapies exert a neuroprotective effect, as well as the mode of administration, the duration of therapy, etc. Therefore, until a powerful strategy is found to improve the consequences of suffocation, this topic will continue to be the subject of intensive research in the future.

Preterm birth buccal cell epigenetic biomarkers to facilitate preventative medicine

Preterm birth is the major cause of newborn and infant mortality affecting nearly one in every ten live births. The current study was designed to develop an epigenetic biomarker for susceptibility of preterm birth using buccal cells from the mother, father, and child (triads). An epigenome-wide association study (EWAS) was used to identify differential DNA methylation regions (DMRs) using a comparison of control term birth versus preterm birth triads. Epigenetic DMR associations with preterm birth were identified for both the mother and father that were distinct and suggest potential epigenetic contributions from both parents. The mother (165 DMRs) and female child (136 DMRs) at p < 1e-04 had the highest number of DMRs and were highly similar suggesting potential epigenetic inheritance of the epimutations. The male child had negligible DMR associations. The DMR associated genes for each group involve previously identified preterm birth associated genes. Observations identify a potential paternal germline contribution for preterm birth and identify the potential epigenetic inheritance of preterm birth susceptibility for the female child later in life. Although expanded clinical trials and preconception trials are required to optimize the potential epigenetic biomarkers, such epigenetic biomarkers may allow preventative medicine strategies to reduce the incidence of preterm birth.

Effects of Arterial Carbon Dioxide Tension on Cerebral and Somatic Regional Tissue Oxygenation and Blood Flow in Neonates After the Norwood Procedure With Deep Hypothermic Cardiopulmonary Bypass

Neonates undergoing the Norwood procedure for hypoplastic left heart syndrome are at higher risk of impaired systemic oxygen delivery with resultant brain, kidney, and intestinal ischemic injury, shock, and death. Complex developmental, anatomic, and treatment-related influences on cerebral and renal-somatic circulations make individualized treatment strategies physiologically attractive. Monitoring cerebral and renal circulations with near infrared spectroscopy can help drive rational therapeutic interventions. The primary aim of this study was to describe the differential effects of carbon dioxide tension on cerebral and renal circulations in neonates after the Norwood procedure. Using a prospectively-maintained database of postoperative physiologic and hemodynamic parameters, we analyzed the relationship between postoperative arterial carbon dioxide tension and tissue oxygen saturation and arteriovenous saturation difference in cerebral and renal regions, applying univariate and multivariate multilevel mixed regression techniques. Results were available from 7,644 h of data in 178 patients. Increases in arterial carbon dioxide tension were associated with increased cerebral and decreased renal oxygen saturation. Differential changes in arteriovenous saturation difference explained these effects. The cerebral circulation showed more carbon dioxide sensitivity in the early postoperative period, while sensitivity in the renal circulation increased over time. Multivariate models supported the univariate findings and defined complex time-dependent interactions presented graphically. The cerebral and renal circulations may compete for blood flow with critical limitations of cardiac output. The cerebral and renal-somatic beds have different circulatory control mechanisms that can be manipulated to change the distribution of cardiac output by altering the arterial carbon dioxide tension. Monitoring cerebral and renal circulations with near infrared spectroscopy can provide rational physiologic targets for individualized treatment.

Non-invasive monitoring of saliva can be used to identify oxidative stress biomarkers in preterm and term newborn infants

AIM

The aim of this study was to appraise the feasibility and reproducibility of applying a validated analytical method to determine salivary oxidative stress biomarkers in newborn infants.

METHODS

Prospective observational single-centre study was carried out in level III neonatal intensive care unit. Eligible patients were preterm infants and healthy full-term newborn infants. Salivary samples were analysed in the chromatographic system.

RESULTS

A total of 23 premature newborn infants and 13 full-term newborns were included. We analysed salivary levels of oxidative stress biomarkers for 5-F_2t isoprostane, 15-E_2t isoprostane, prostaglandin E₂ and prostaglandin F2α. The multivariate predictive model showed a positive association between female and 5-F_2t isoprostonae, and between female sex and prostglandin F2α. In addition, we found a positive association between gestational age and levels of prostaglandin E₂ . Furthermore, in the premature group, we found a positive association between the inspired fraction of oxygen and levels of prostaglandin G₂ .

CONCLUSION

We identified and determined lipid peroxidation biomarkers in term and preterm newborn infants' saliva using specific and validated mass spectrometry technology.

Oxygen Toxicity to the Immature Lung-Part I: Pathomechanistic Understanding and Preclinical Perspectives

In utero, the fetus and its lungs develop in a hypoxic environment, where HIF-1α and VEGFA signaling constitute major determinants of further development. Disruption of this homeostasis after preterm delivery and extrauterine exposure to high fractions of oxygen are among the key events leading to bronchopulmonary dysplasia (BPD). Reactive oxygen species (ROS) production constitutes the initial driver of pulmonary inflammation and cell death, altered gene expression, and vasoconstriction, leading to the distortion of further lung development. From preclinical studies mainly performed on rodents over the past two decades, the deleterious effects of oxygen toxicity and the injurious insults and downstream cascades arising from ROS production are well recognized. This article provides a concise overview of disease drivers and different therapeutic approaches that have been successfully tested within experimental models. Despite current studies, clinical researchers are still faced with an unmet clinical need, and many of these strategies have not proven to be equally effective in clinical trials. In light of this challenge, adapting experimental models to the complexity of the clinical situation and pursuing new directions constitute appropriate actions to overcome this dilemma. Our review intends to stimulate research activities towards the understanding of an important issue of immature lung injury.

A Reductive Metabolic Switch Protects Infants with Transposition of Great Arteries Undergoing Atrial Septostomy against Oxidative Stress

Transposition of the great arteries (TGA) is one of the most common cyanotic congenital heart diseases requiring neonatal surgical intervention. Parallel circulations that result in impaired cerebral oxygen delivery already in utero may lead to brain damage and long-term neurodevelopmental delay. Balloon atrial septostomy (BAS) is often employed to mix deoxygenated and oxygenated blood at the atrial level. However, BAS causes a sudden increase in arterial blood oxygenation and oxidative stress. We studied changes in oxygen saturation as well as metabolic profiles of plasma samples from nine newborn infants suffering from TGA before and until 48 h after undergoing BAS. The plasma metabolome clearly changed over time and alterations of four metabolic pathways, including the pentose phosphate pathway, were linked to changes in the cerebral tissue oxygen extraction. In contrast, no changes in levels of lipid peroxidation biomarkers over time were observed. These observations suggest that metabolic adaptations buffer the free radical burst triggered by re-oxygenation, thereby avoiding structural damage at the macromolecular level. This study enhances our understanding of the complex response of infants with TGA to changes in oxygenation induced by BAS.

Age-related changes in thyroid hormones, some serum oxidative biomarkers and trace elements and their relationships in healthy Saanen goat kids during the first three month of age

BACKGROUND

Early-life diseases in dairy animals are main causes of economic loss in livestock production. Oxidative stress (OS) and thyroid hormones are important inter-related components in the normal physiology of this critical period of life. However, limited information regarding their physiology in goat kids is available. This study was conducted to investigate the age-related changes of thyroid hormones, some serum oxidative biomarkers and trace elements in healthy Saanen goat kids.

METHODS

Nineteen newborn healthy Saanen goat kids (14 females and five males) were studied longitudinally from birth until three months of age. Blood sampling was performed 24-48 h after birth and was repeated on 10 ± 2, 28 ± 2, 56 ± 2 and 84 ± 2 days of age. The serum levels of thyroid hormones, malondialdehyde (MDA), reduced glutathione (GSH), total antioxidant capacity (TAC), selenium (Se), manganese (Mn) and molybdenum (Mo) were measured.

RESULTS

Age-related changes were observed for all measured variables except for MDA (p < 0.05). A decreasing trend was detected throughout the study in thyroid hormones, T3: T4 ratio and Mn (p < 0.01). Some factors decreased from birth to day 10 (Se) or day 28 (TAC and GSH) and followed by an increasing trend that extended to day 84 (p < 0.01). There were significant correlations between thyroid hormones and TAC, as well as Mn levels (p < 0.05).

CONCLUSIONS

These results imply that specific age-related reference values are essential for proper interpretation of the serum level of thyroid hormones and Mn in Saanen goat kids during the first three months of life. In addition, given the high level of thyroid hormones particularly during the first days of life, and their relationship with oxidative biomarkers and trace elements, improving the antioxidant system in this critical period is essential.

Biomarkers of Oxidative Stress for Neonatal Lung Disease

The transition from prenatal to postnatal life causes a significant increase in arterial oxygen tension and the activation of metabolic pathways enabling the newborn's adaptation to the extra-uterine environment. The balance between pro-oxidant and anti-oxidant systems is critical to preserve cellular functions. Indeed, oxidative stress (OS) occurs when the production of free radicals is not balanced by the activity of intracellular antioxidant systems, contributing to cellular and tissue damage. Perinatal OS may have serious health consequences during the postnatal period and later in life. Namely, OS has been recognized as the major cause of lung injury in newborns, especially those preterm born, due to their immature lung and antioxidant systems. The development of OS biomarkers has gained increasing research interest since they may provide useful insights about pathophysiological pathways underlying OS-mediated pulmonary diseases in newborns. Moreover, their implementation in clinical settings may help to early identify high risk-newborns and to provide targeted treatment. Ideally, a biomarker should demonstrate ease of use, biological validity and reproducibility, high sensitivity and specificity. However, none of the clinically validated biomarkers so far have been qualified for neonatal lung disease. Additionally, the complex technical procedures and the high cost of such determinations have hampered the use of OS biomarkers in clinical practice. This review aims to evaluate the current evidence on the application of biomarkers of oxidative stress for neonatal lung disease and exploring the most relevant issues affecting their implementation in practice, as well as the associated evidence gaps and research limitations.

Tamarix articulata Extracts Exhibit Antioxidant Activity and Offer Protection against Hydrogen Peroxide-Mediated Toxicity to Human Skin Fibroblasts

Tamarix articulata (TA) is a wild halophytic plant growing in extremely harsh environmental conditions in the deserts of Saudi Arabia. Evaluating the protective effect of the methanolic extract of different parts (fresh and dry leaves, stem, and root) of TA was determined by MTT assay using Hs27 skin fibroblasts as the cellular model. The study was designed and conducted in two sets. The first set assesses the toxicity profile of TA extracts in both concentration- and time-dependent ways on Hs27 cells. Our MTT results showed that methanolic extracts from all four parts of TA at varying doses (27.5, 55, 110, and 220 μg/mL) display negligible toxicity when exposed for 4 h. However, exposure of Hs27 cells to varying doses of all four TA extracts for 24 and 48 h promotes significant 23%, 24%, 26%, and 25% (p < 0.05) and 35%, 36%, 39%, and 41% (p < 0.05) cell toxicity at 220 μg/mL of all four TA extracts compared to untreated control cells. To evaluate the protection offered by TA extracts against H₂O₂, we perform a second set of experiments to preincubate Hs27 cells with the TA extracts in both dose- and time-dependent way. This is followed by 300 μM hydrogen peroxide- (H₂O₂-) mediated oxidative insult for 1 h. Using MTT assay, we found that methanolic extracts of TA at different time points (4, 24, and 48 h) and higher doses (220 μg/mL) provide significant protection in cell viability when challenged with H₂O₂-induced oxidative stress in Hs27 cells. The protective effect was more pronounced at 48 h and 220 μg/mL and the amounts were 39%, 41%, 41%, and 44% for stem, root, fresh leaf, and dry leaf TA extracts (p < 0.05), respectively, compared to untreated cells (2–4%). Collectively, the current study demonstrates that methanolic extracts of TA contain potential bioactive compounds and offer significant protection against H₂O₂-mediated oxidative stress in Hs27 skin fibroblasts.

Oxidative Stress in Preterm Infants: Overview of Current Evidence and Future Prospects

Preterm birth (PTB), defined as parturition prior to 37 weeks of gestation, is the leading cause of morbidity and mortality in the neonatal population. The incidence and severity of complications of prematurity increase with decreasing gestational age and birthweight. The aim of this review study is to select the most current evidence on the role of oxidative stress in the onset of preterm complication prevention strategies and treatment options with pre-clinical and clinical trials. We also provide a literature review of primary and secondary studies on the role of oxidative stress in preterm infants and its eventual treatment in prematurity diseases. We conducted a systematic literature search of the Medline (Pubmed), Scholar, and ClinicalTrials.gov databases, retroactively, over a 7-year period. From an initial 777 articles identified, 25 articles were identified that met the inclusion and exclusion criteria. Of these, there were 11 literature reviews: one prospective cohort study, one experimental study, three case-control studies, three pre-clinical trials, and six clinical trials. Several biomarkers were identified as particularly promising, such as the products of the peroxidation of polyunsaturated fatty acids, those of the oxidation of phenylalanine, and the hydroxyl radicals that can attack the DNA chain. Among the most promising drugs, there are those for the prevention of neurological damage, such as melatonin, retinoid lactoferrin, and vitamin E. The microbiome also has an important role in oxidative stress. In conclusion, the most recent studies show that a strong relationship between oxidative stress and prematurity exists and that, unfortunately, there is still little therapeutic evidence reported in the literature.

Blood and urine biomarkers associated with long-term respiratory dysfunction following neonatal hyperoxia exposure: Implications for prematurity and risk of SIDS

Former preterm infants, many of whom required supplemental O₂ support, exhibit sleep disordered breathing and attenuated ventilatory responses to acute hypoxia (HVR) beyond their NICU stay. There is an increasing awareness that early detection of biomarkers in biological fluids may be useful predictors/identifiers of short- and long-term morbidities. In the present study, we identified serotonin (5-HT), dopamine (DA) and hyaluronan (HA) as three potential biomarkers that may be increased by neonatal hyperoxia and tested whether they would be associated with an impaired HVR in a rat model of supplemental O₂ exposure. Neonatal rats (postnatal age (P) 6 days, P6) exposed to hyperoxia (40% FIO₂, 24 h/day between P1-P5 days of age) exhibited an attenuated early (1 min), but not the late (4-5 min) phase of the HVR compared to normoxia control rats; the attenuated early phase HVR was associated with increased levels of DA (urine and serum), 5-HT (platelet poor plasma only, PPP), and HA (serum only). At P21, both the early and late phases of the HVR were attenuated, but serum and urine levels of all 3 biomarkers were similar to age-matched control rats. These data indicate that changes in several serum and/or urine biomarkers (5-HT, DA, and HA) following short-term (days) neonatal hyperoxia can signify long-term (weeks) respiratory control dysfunction. Further studies are needed to determine whether early detection of similar biomarkers could be convenient predictors of increased risk of abnormalities in respiratory control including sleep disordered breathing in former preterm infants who had received prior supplemental O₂ and who might also be at increased risk of SIDS.

Oxidative stress biomarkers in the perinatal period: Diagnostic and prognostic value

Perinatal oxidative stress (OS) is involved in the physiopathology of many pregnancy-related disorders and is largely responsible for cellular, tissue and organ damage that occur in the perinatal period especially in preterm infants, leading to the so-called "free-radicals related diseases of the newborn". Reliable biomarkers of lipid, protein, DNA oxidation and antioxidant power in the perinatal period have been demonstrated to show specificity for the disease, to have prognostic power or to correlate with disease activity. Yet potential clinical applications of oxidative stress biomarkers in neonatology are still under study. Overcoming the technical and economic difficulties that preclude the use of OS biomarkers in the clinical practice is a challenge that needs to be overcome to identify high-risk subjects and to predict their short- and long-term outcome. Cord blood, urine and saliva represent valid and ethically acceptable biological samples for investigations in the perinatal period.

Oxygen in the neonatal period: Oxidative stress, oxygen load and epigenetic changes

Preterm infants frequently require positive pressure ventilation and oxygen supplementation in the first minutes after birth. It has been shown that the amount of oxygen provided during stabilization, the oxygen load, if excessive may cause hyperoxia, and oxidative damage to DNA. Epidemiologic studies have associated supplementation with pure oxygen in the first minutes after birth with childhood cancer. Recent studies have shown that the amount of oxygen supplemented to preterm infants after birth modifies the epigenome. Of note, the degree of DNA hyper-or hypomethylation correlates with the oxygen load provided upon stabilization. If these epigenetic modifications would persist, oxygen supplied in the first minutes after birth could have long term consequences. Further studies with a robust power calculation and long-term follow up are needed to bear out the long-term consequences of oxygen supplementation during postnatal stabilization of preterm infants.

Oxidative stress - Related spontaneous preterm delivery challenges in causality determination, prevention and novel strategies in reduction of the sequelae

Spontaneous preterm birth (PTB) is one of the major complications of pregnancy and the main cause of neonatal mortality and morbidity. Despite the efforts devoted to the understanding of this obstetrical syndrome and improved medical care, there has been a tendency for the PTB rate to increase in the last decades globally. The costs of the screening for spontaneous PTB, its management, and treatment of the sequelae represent a major burden to the health service economy of high-income countries. In this scenario, it has been widely acknowledged that oxidative stress (OS) plays an important role in the pathogenicity of human disease in wide range of areas of medicine. There is an emerging evidence that an imbalance between pro-and-antioxidants may be associated with spontaneous PTB. However, there are still many controversies on the mechanisms by which OS are involved in the pathogenesis of prematurity. Moreover, the crucial question whether the OS is the cause or consequence of the disease is yet to be answered. The purpose of this article is to briefly summarize the current knowledge and controversies on oxidative stress-related spontaneous PTB and to give a critical approach on future perspectives on this topic as a classical example of translational medicine. Placenta-mediated pregnancy adverse outcome associated with OS leading to iatrogenic PTB (e.g. pre-eclampsia, intrauterine growth restriction, gestational diabetes) will not be discussed.

Brain oxidative damage in murine models of neonatal hypoxia/ischemia and reoxygenation

The brain is one of the main organs affected by hypoxia and reoxygenation in the neonatal period and one of the most vulnerable to oxidative stress. Hypoxia/ischemia and reoxygenation leads to impairment of neurogenesis, disruption of cortical migration, mitochondrial damage and neuroinflammation. The extent of the injury depends on the clinical manifestation in the affected regions. Preterm newborns are highly vulnerable, and they exhibit severe clinical manifestations such as intraventricular hemorrhage (IVH), retinopathy of prematurity (ROP) and diffuse white matter injury (DWMI) among others. In the neonatal period, the accumulation of high levels of reactive oxygen species exacerbated by the immature antioxidant defense systems in represents cellular threats that, if they exceed or bypass physiological counteracting mechanisms, are responsible of significant neuronal damage. Several experimental models in mice mimic the consequences of perinatal asphyxia and the use of oxygen in the reanimation process that produce brain injury. The aim of this review is to highlight brain damage associated with oxidative stress in different murine models of hypoxia/ischemia and reoxygenation.

Intermittent hypoxemia and oxidative stress in preterm infants

Intermittent hypoxemia events (IH) are common in extremely preterm infants and are associated with many poor outcomes including retinopathy or prematurity, wheezing, bronchopulmonary dysplasia, cognitive or language delays and motor impairment. More recent data in animal and rodent models have suggested that specific patterns of IH may increase the risk for morbidity. The pathway by which these high risk patterns of IH initiate a pathological cascade is unknown but animal models suggest that oxidative stress may play a role. This review describes early postnatal patterns of IH in preterm infants, their relationship with morbidity, oxidative stress biomarkers relevant to the newborn infant and the relationship between IH and reactive oxygen species.

Bronchopulmonary dysplasia: what are its links to COPD?

Emerging evidence suggests that adverse early life events can affect long-term health trajectories throughout life. Preterm birth, in particular, is a significant early life event that affects approximately 10% of live births. Worldwide, prematurity is the number one cause of death in children less than 5 years of age and has been shown to disrupt normal lung development with lasting effects into adult life. Along with impaired lung development, interventions used to support gas exchange and other sequelae of prematurity can lead to the development of bronchopulmonary dysplasia (BPD). BPD is a chronic respiratory disease of infancy characterized by alveolar simplification, small airways disease, and pulmonary vascular changes. Although many survivors of BPD improve with age, survivors of BPD often have chronic lung disease characterized by airflow obstruction and intermittent pulmonary exacerbations. Long-term lung function trajectories as measured by FEV1 can be lower in children and adults with a history BPD. In this review, we discuss the epidemiology and manifestations of BPD and its long-term consequences throughout childhood and into adulthood. Available evidence suggests that disrupted lung development, genetic susceptibility and subsequent environment and infectious events that occur in prenatal and postnatal life likely increase the predisposition of children with BPD to develop early onset chronic obstructive pulmonary disease (COPD). The reviews of this paper are available via the supplemental material section.