Young hearts, early risks: novel cardiovascular biomarkers in former very preterm infants at kindergarten age.

BACKGROUND: Preterm birth is associated with long-term cardiovascular morbidity and mortality. In adults, fibroblast growth factor-23 (FGF-23), α-Klotho, and secretoneurin have all garnered attention as cardiovascular biomarkers, but their utility in pediatric populations has not yet been ascertained. The aim of this pilot study was to evaluate these novel cardiovascular biomarkers and their association with indicators of cardiovascular impairment in the highly vulnerable population of former very preterm infants. METHODS: Five- to seven-year-old children born at < 32 weeks' gestation were eligible for the study. Healthy same-aged children born at term served as controls. Biomarkers were quantified in fasting blood samples, and echocardiographic measurements including assessment of aortic elastic properties were obtained. RESULTS: We included 26 former very preterm infants and 21 term-born children in the study. At kindergarten age, former very preterm infants exhibited significantly higher plasma concentrations of biologically active intact FGF-23 (iFGF-23; mean 43.2 pg/mL vs. 29.1 pg/mL, p = 0.003) and secretoneurin (median 93.8 pmol/L vs. 70.5 pmol/L, p = 0.046). iFGF-23 inversely correlated with distensibility of the descending aorta. CONCLUSION: In preterm-born children, iFGF-23 and secretoneurin both offer prospects as valuable cardiovascular biomarkers, potentially allowing for risk stratification and timely implementation of preventive measures. IMPACT: Former very preterm infants have increased plasma concentrations of the novel cardiovascular biomarkers intact fibroblast growth factor-23 (iFGF-23) and secretoneurin at kindergarten age. Increases in iFGF-23 concentrations are associated with decreased distensibility of the descending aorta even at this early age. Monitoring of cardiovascular risk factors is essential in individuals with a history of preterm birth. Both iFGF-23 and secretoneurin hold promise as clinically valuable biomarkers for risk stratification, enabling the implementation of early preventive measures.

Association of aEEG and brain injury severity on MRI at term-equivalent age in preterm infants.

AIM: Measures to detect and monitor brain injury in preterm infants are amplitude-integrated electroencephalography (aEEG) and magnetic resonance imaging (MRI). To investigate the association between aEEG and MRI in a large cohort of preterm infants. Five hundred and twenty-three preterm infants were included in the study. METHODS: AEEG was interpreted for the total maturation score (TMS) according to Burdjalov. Cerebral MRI was evaluated using a validated scoring system by Kidokoro. RESULTS: One hundred and forty-six infants (27.9%) showed some form of brain injury, with 111 infants (21.2%) showing mild injury and 35 (6.7%) showing severe injury. TMS were significantly higher in infants without injury compared to severe injury. When comparing infants with isolated intraventricular haemorrhage  to infants without brain injury, TMS were significantly lower. CONCLUSION: Prediction of adverse outcome is an important aspect of neonatal care. The combination of diagnostic measures evaluating brain injury might enhance our abilities in neonatal care to provide accurate information about later outcome. Early aEEG is predictive for the severity of brain injury detected by MRI at term-equivalent age. Whether aEEG is also predictive for neurodevelopmental outcome needs to be further investigated in relation to the various patterns of preterm brain injury.

Postnatal cytomegalovirus infections did not alter amplitude-integrated electroencephalography signals or general movements in preterm infants.

AIM: Controversy prevails about whether postnatal cytomegalovirus (CMV) infections are associated with adverse neurodevelopmental outcomes. We aimed to investigate whether amplitude-integrated electroencephalography (aEEG) signals and General Movement Assessment (GMA) scores differed in very preterm infants with postnatal CMV infections. METHODS: This was a retrospective single-centre study, conducted at Innsbruck Medical University Hospital, Austria, between February 2011 and November 2018. We screened 461 infants born before 32 weeks of gestation for CMV infections. Their aEEG signals were analysed for the distribution of background activity patterns and their total maturation scores and component scores. The GMA was performed at 36 weeks of postmenstrual age, term-equivalent age and 3 months of corrected age. RESULTS: We studied 20 infants (55% male) with postnatal CMV infections, born at a mean gestational age of 28.1 (25.3-30.7) weeks and a mean birth weight of 1064 (640-1600) grams. No differences were found in the aEEG signals or GMA scores between these infants and 441 uninfected controls. CONCLUSION: Preterm infants with postnatal CMV infections showed no alterations in neonatal aEEG signals or GMA scores, compared with the uninfected controls. Longer follow-up studies are needed to evaluate the effect of postnatal cytomegalovirus infections on later neurodevelopmental outcomes.

Very preterm birth results in later lower platelet activation markers.

BACKGROUND: Premature birth entails an adverse cardiovascular risk profile, but the underlying mechanisms are insufficiently understood. Here, we employed an unbiased cardiovascular proteomics approach to profile former very preterm-born preschoolers. METHODS: This observational study investigated differences in plasma concentrations of 79 proteins, including putative cardiovascular biomarkers between very preterm- and term-born children on average 5.5 years old (53.1% male) using multiple-reaction monitoring mass spectrometry. RESULTS: Very preterm-born (n = 38; median gestational age 29.6 weeks) compared to term-born (n = 26; 40.2 weeks) children featured lower plasma concentrations of platelet factor 4 (PLF4; -61.6%, P < 0.0001), platelet basic protein (CXCL7; -57.8%, P < 0.0001), and hemoglobin subunit beta (-48.3%, P < 0.0001). Results remained virtually unchanged when adjusting for complete blood count parameters, including platelet count. Conversely, whole blood hemoglobin was higher (+7.62%, P < 0.0001) in preterm-born children. CONCLUSIONS: Very preterm birth was associated with decreased markers of platelet activation among preschoolers. These findings are consistent with reduced platelet reactivity persisting from very preterm birth to a preschool age. IMPACT: Former very preterm-born preschoolers featured reduced levels of platelet activation markers. While lower platelet reactivity in very preterm-born compared to term-born infants in the first days of life was established, it was unknown when, if at all, reactivity normalizes. The current study suggests that platelet hyporeactivity due to very preterm birth persists at least up to a preschool age. "Immaturity of the hemostatic system" may be a persistent sequel of preterm birth, but larger studies are needed to investigate its potential clinical implications.

Amplitude-integrated electroencephalography shows alterations in children born preterm displaying poor literacy precursor skills.

AIM: To assess whether amplitude-integrated electroencephalography (aEEG) alterations in the newborn period are associated with poor precursor skills of literacy at five years of age in children born preterm. METHODS: Between October 2007 and September 2011 248 preterm infants were eligible for the study at Innsbruck Medical University Hospital. aEEG was analysed for dominating background activity, calculation of the percentage of continuous activity, the Burdjalov scoring system, the minimum, mean and maximum amplitude. At the age of five years, we evaluated preterm born children by the Bielefelder screening (BISC) to assess for early diagnosis of reading problems and weak spelling and classified them as normal performers (n = 64) or poor performers (n = 20). Completion of testing was not possible for one infant. RESULTS: The minimum amplitude was significantly lower in the poor BISC performance group as compared to the normal BISC performance group at postnatal week two. The percentage of continuous background activity was significantly higher in infants with normal BISC performance than in infants with poor BISC performance at postnatal week three. CONCLUSION: Children with poor developed precursor skills of literacy showed alterations in aEEG signals. The aEEG could be useful in further diagnosing preterm infants at risk for developmental complications.

Former very preterm infants show alterations in plasma amino acid profiles at a preschool age.

BACKGROUND: Amino acid analysis is a valuable tool for cardiovascular risk assessment. Preterm infants display plasma amino acid changes in the newborn period. Whether these changes persist is unknown to date. The aim of this study was to assess whether former very preterm infants (VPI) show alterations in amino acid patterns indicative of an unfavorable cardiovascular risk profile at a preschool age. METHODS: From 5-7 y-old children born at term or <32 wk gestation (VPI) were included in the study. Plasma amino acid concentrations were determined after an overnight fast. RESULTS: 29 former term infants and 79 former VPI were included in the study. Former VPI showed changes in various plasma amino acids including glutamine, arginine, citrulline, tryptophan, glutamate, ornithine, and taurine. Branched-chain amino acids were lower, alanine/lysine ratios significantly higher in the preterm population. CONCLUSION: Former VPI show altered plasma amino acid profiles indicative of a dualistic cardiovascular risk profile (e.g., potentially beneficial elevations in citrulline, arginine, glutamine, and tryptophan, but also raised alanine/lysine ratios, low ornithine and taurine levels) at a preschool age. Whether this is associated with an adverse cardiovascular outcome has to be addressed by future studies. Long-term cardiometabolic follow-up of VPI might be warranted.

Aortic Elastic Properties in Preschool Children Born Preterm.

OBJECTIVE: Preterm birth predisposes children to the development of cardiovascular diseases in adulthood. The aim of this study was to characterize elastic properties of the aorta at preschool age and test the hypothesis that prematurity is associated with decreased aortic distensibility and increased stiffness, both of which are predictors of increased cardiovascular risk. APPROACH AND RESULTS: In an observational study of 76 five- to seven-year-old children born at a gestational age <32 weeks and 79 term-born controls, elastic parameters of the ascending and descending abdominal aorta were determined noninvasively by means of M mode echocardiographic tracings and calculated using computerized wall contour analysis. Compared with children born at term, the preterm group showed significantly reduced distensibility and increased stiffness of the descending abdominal aorta. These results remained significant under multivariable adjustment for birth weight z score, maternal smoking in pregnancy, maternal education, family history of cardiovascular disease, breastfeeding, childhood nutrition, and current body mass index z score (multivariable odds ratios and 95% confidence intervals 5.1, 1.7-15.9; P=0.005 and 2.8, 1.0-7.9; P=0.046, respectively). Further adjustment for intravenous lipid therapy attenuated the strength of association. Elastic properties of the ascending aorta did not differ between the 2 study groups. CONCLUSIONS: Children born preterm are characterized by decreased elastic properties of the descending abdominal aorta potentially attributable to impaired viscoelastic properties of and lipid damage to the aorta. Clinical follow-up of preterm infants with a focus on aortic elastic properties may be useful for tailoring early prevention programs and counteracting cardiovascular risk in adulthood.

An unusual cause of inspiratory stridor in the newborn: congenital pharyngeal teratoma--a case report.

BACKGROUND: Neonatal inspiratory stridor is an important examination finding that requires immediate and adequate evaluation of the underlying etiology. Depending on the severity of the airway obstruction and the presence or absence of associated symptoms such as respiratory distress and feeding problems, early initiation of a complete diagnostic workup can be crucial. The most common cause of neonatal inspiratory stridor is laryngomalacia, however, several differential diagnoses need to be investigated. More rare causes include oral or laryngeal masses. Teratomas of the head and neck region are one of the most unusual causes of respiratory distress during the neonatal period. We present a case of a mature teratoma in the oropharynx presenting with airway obstruction in a newborn infant. CASE PRESENTATION: A four-day-old female Caucasian infant was admitted to the neonatal intensive care unit of our hospital because of inspiratory stridor and profound desaturations while feeding. Diagnostic workup by ultrasound, magnetic resonance imaging and flexible endoscopy revealed a pediculated lesion in the pharyngeal region causing intermittent complete airway obstruction. The mass was surgically removed by transoral laser resection on the seventh day of life. Histological evaluation was consistent with a mature teratoma without any signs of malignancy. The further hospital course was uneventful, routine follow-up examinations at 3, 6 and 9 months of age showed no evidence of tumor recurrence. CONCLUSION: Neonatal stridor is a frequent symptom in the neonatal period and is mostly caused by non-life-threatening pathologies. On rare occasions, however, the underlying conditions are more critical. A careful stepwise diagnostic investigation to rule out these conditions, to identify rare causes and to initiate early treatment is therefore warranted.

Early Brain Activity in Very Preterm Infants of Mothers with Gestational Diabetes Mellitus: A Pilot Study.

INTRODUCTION: Neurological consequences of preterm infants born to mothers with gestational diabetes mellitus (GDM) are unclear. In this pilot study, we investigated the effect of GDM on brain activity in very preterm infants. METHODS: Preterm infants <32 gestational weeks of mothers with GDM compared to gestational age- and sex-matched controls born between 2011 and 2018 were included. Amplitude-integrated electroencephalography (aEEG) was assessed for total maturation and individual component scores according to Burdjalov and colleagues, the dominating visual background, and the presence of sleep-wake cycles per hour in the first 72 h of life and weekly at days 7, 14, 21, and 28. RESULTS: We included 47 infants of mothers with GDM and 94 control infants. Both the aEEG total maturation score and its individual component scores, as well as the percentage of continuous background pattern, increased equally during the first 4 weeks after birth in both groups. GDM-exposed infants showed a slightly but significantly higher number of sleep-wake cycles per hour. CONCLUSION: We found normal maturation of brain activity in the first 4 weeks after birth in very preterm infants born to mothers with GDM, not differing from a very preterm control group. The higher number of sleep-wake cycles per hour in GDM-exposed infants could indicate transiently enhanced maturation. Further studies on brain activity and brain development in very preterm infants of mothers with GDM are needed to validate our results.

Cardiac biomarkers and left ventricular systolic function in former very preterm infants and term controls at preschool age.

Introduction: Due to improvements in perinatal care, survival rates of preterm infants have improved during the last decades. However, these infants remain at risk of developing cardiovascular sequelae later in life. This study aimed to investigate the cardiac biomarkers and left ventricular systolic function in former preterm infants in comparison with term controls at preschool age. Methods: The study included children aged 5-7 years old born below 32 weeks of gestational age. The control group consisted of same-age children born at term. Basic data of study participants were collected using questionnaires and follow-up databases. During the study visit, we recorded anthropometric data and blood pressure readings, determined high-sensitive cardiac troponin T (hs-cTnT) and N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) concentrations, and calculated fractional shortening (FS) and left ventricular mass (LVM). Results: Term-born (n = 25; median gestational age, 40.1 weeks) compared with preterm-born infants (n = 80; median gestational age 29.6 weeks) showed no significant differences in the median concentration of hs-cTnT [median, 3.5 (IQR 3.5; 3.5) vs. 3.5 (3.5; 3.5) ng/L, p = 0.328] and the median concentration of NT-pro-BNP [median, 91.0 (IQR 40.8; 150.3) vs. 87.5 (50.1; 189.5) ng/L, p = 0.087]. FS and LVM/LVMI were not significantly different between the two groups. Conclusion: At preschool age, we observed no significant differences in cardiac biomarkers and left ventricular systolic function in preterm infants. Further studies are warranted to explore the potential of cardiac biomarkers as a prognostic tool for subclinical cardiac alterations after preterm birth.

Factors Influencing Breast Milk Antibody Titers during the Coronavirus Disease 2019 Pandemic: An Observational Study.

The COVID-19 pandemic has highlighted the role of breastfeeding in providing passive immunity to infants via specific anti-SARS-CoV-2 antibodies in breast milk. We aimed to quantify these antibodies across different lactation stages and identify influencing factors. This prospective study involved mother-child dyads from Innsbruck University Hospital, Austria, with a positive maternal SARS-CoV-2 test during pregnancy or peripartum between 2020 and 2023. We collected breast milk samples at various lactation stages and analyzed anti-Spike S1 receptor-binding domain (S1RBD) immunoglobulins (Ig). Maternal and neonatal data were obtained from interviews and medical records. This study included 140 mothers and 144 neonates. Anti-S1RBD-IgA (72.0%), -IgG (86.0%), and -IgM (41.7%) were highly present in colostrum and decreased as milk matured. Mothers with natural infection and vaccination exhibited higher anti-S1RBD-IgA and -IgG titers in all milk stages. Mothers with moderate to severe infections had higher concentrations of anti-S1RBD-IgA and -IgG in transitional milk and higher anti-S1RBD-IgA and -IgM in mature milk compared to those with mild or asymptomatic infections. Variations in antibody responses were also observed with preterm birth and across different virus waves. This study demonstrates the dynamic nature of breast milk Ig and underscores the importance of breastfeeding during a pandemic.

In vivo and in vitro evaluation of the effect of 2-(4-morpholinethyl)1-phenylcyclohexanecarboxylate on inflammation-sensitized hyperoxia-induced developing brain injury.

Supraphysiological oxygen concentrations are toxic to the developing brain. Inflammatory processes increase the risk for brain injury. Sigma-1 receptor agonists are potent suppressors of inflammation-related events and are powerful immunomodulatory and antioxidative agents. Neuroprotective effects of sigma-1 receptor agonists have been described previously for neonatal and adult models of brain injury. The aim of this study was to assess the selective sigma-1 receptor agonist 2-(4-morpholinethyl)1-phenylcyclohexanecarboxylate (PRE-084) in models of inflammation-sensitized hyperoxia-induced developing brain injury. For in vivo studies, rat pups were randomly presensitized with 1) lipopolysaccharide or 2) vehicle on postnatal day 3. On day 6, pups received either 1) PRE-084 or 2) vehicle and were subsequently exposed to hyperoxic conditions for 6, 12, or 24 hr. At the end of exposure, animals were sacrificed and brains were processed for caspase-3 analysis using immunohistochemistry and Western blotting. For in vitro studies, oligodendroglial cells were subjected to hyperoxic conditions in the presence or absence of proinflammatory cytokines and PRE-084. Cell membrane integrity and cell viability were assessed by means of lactate dehydrogenase and 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assays. Inflammatory presensitization significantly increased hyperoxia-induced injury both in vivo and in vitro. PRE-084 administration did not attenuate damage. Sigma-1 receptor agonists have been described as a promising therapeutic strategy for brain injury. We were not able to confirm this in the present model. The exact mechanisms of action of sigma-1 receptor agonists as well as the pathophysiologic pathways involved in hyperoxia-induced injury in the developing brain remain to be elucidated.

Striatal Lacunar Infarction in a Late Preterm Infant Born to a Mother with Active Peripartum SARS-CoV-2 Infection.

Background: The current literature suggests that neonatal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections generally have a mild course. Data on how in utero exposure to maternal infection affects neonatal health outcomes are limited, but there is evidence that neurological damage to the fetus and thromboembolic events may occur. Case Presentation. We describe the case of a late preterm infant, who presented with striatal lacunar infarction in the neonatal period, born to a mother with active peripartum SARS-CoV-2 infection. Diagnostic workup did not identify risk factors apart from the maternal SARS-CoV-2 infection. Repeated reverse transcription-polymerase chain reaction (RT-PCR) tests for SARS-CoV-2 using oropharyngeal swab specimens of the patient were negative. IgG, but not IgM antibodies against spike protein S1 receptor-binding domain (S1RBD) epitope were detectable in umbilical cord blood and neonatal serum collected at 48 hours of life. Anti-SARS-CoV-2 total antibody titers against nucleocapsid protein in umbilical cord blood were negative. Conclusions: Bearing in mind a possible association of in utero exposure to SARS-CoV-2 and neonatal thromboembolic events, neonatologists should be aware of these complications even in well-appearing preterm infants.

Investigation of secretoneurin as a potential biomarker of brain injury in very preterm infants: A pilot study.

Neurodevelopmental impairment is a significant complication among survivors of preterm birth. To improve outcomes, reliable biomarkers for early detection of brain injury and prognostic assessment are required. Secretoneurin is a promising early biomarker of brain injury in adults and full-term neonates suffering from perinatal asphyxia. Data on preterm infants is currently lacking. The aim of this pilot study was to determine secretoneurin concentrations in preterm infants in the neonatal period, and to assess secretoneurin's potential as a biomarker of preterm brain injury. We included 38 very preterm infants (VPI) born at <32 weeks' gestation in the study. Secretoneurin concentrations were measured in serum samples obtained from the umbilical cord, at 48 hours and 3 weeks of life. Outcome measures included repeated cerebral ultrasonography, magnetic resonance imaging at term-equivalent age, general movements assessment, and neurodevelopmental assessment at a corrected age of 2 years by the Bayley Scales of Infant and Toddler Development, third edition (Bayley-III). In comparison to a term-born reference population, VPI had lower secretoneurin serum concentrations in umbilical cord blood and blood collected at 48 hours of life. When measured at 3 weeks of life, concentrations correlated with gestational age at birth. Secretoneurin concentrations did not differ between VPI with an imaging-based diagnosis of brain injury and those without, but when measured in umbilical cord blood and at 3 weeks of life correlated with and were predictive of Bayley-III motor and cognitive scale scores. Secretoneurin levels in VPI differ from term-born neonates. Secretoneurin seems unsuitable as a diagnostic biomarker of preterm brain injury, but bears some prognostic potential and is worthy of further investigation as a blood-based biomarker of preterm brain injury.

MicroRNA Expression Profiles as Diagnostic and Prognostic Biomarkers of Perinatal Asphyxia and Hypoxic-Ischaemic Encephalopathy.

INTRODUCTION: Perinatal asphyxia is a leading cause of neonatal death. Up to one-third of asphyxiated neonates suffer from hypoxic-ischaemic encephalopathy (HIE) with substantial long-term morbidity. Currently available diagnostic and prognostic tools bear limitations, and additional reliable biomarkers are needed for all stages of clinical management. A novel tool in neuroscientific research is micro-ribonucleic acid (miRNA) profiling. The aim of the present study was to determine miRNA expression profiles of healthy and asphyxiated neonates with and without HIE and to assess their potential as diagnostic and prognostic biomarkers. METHODS: We prospectively enrolled 49 neonates with a gestational age of ≥36 weeks, 15 of which fulfilled the diagnostic criteria of perinatal asphyxia and 34 served as healthy controls. Dried blood spots were collected from umbilical cord blood (UCB) and from venous blood upon admission to neonatal intensive care unit (NICU) and at 48 h of life. Samples were analysed by means of FirePlex™ technology (Abcam, Cambridge, MA, USA). RESULTS: In the UCB, miRNA expression levels of hsa-mir-124-3p, hsa-mir-1285-5p, and hsa-mir-331-5p were significantly lower in asphyxiated neonates compared to healthy controls. Asphyxiated neonates requiring therapeutic hypothermia had significantly increased expression of hsa-miR-30e-5p and significantly decreased expression of hsa-miR-142-3p, hsa-miR-338-3p, hsa-miR-34b-3p, hsa-miR-497-5p, and hsa-miR-98-5p at the time of admission to the NICU. At 48 h, infants suffering from moderate/severe HIE with a poor long-term neurodevelopmental outcome showed a significant increase in hsa-mir-145-5p. DISCUSSION/CONCLUSION: MiRNA profiling shows promise as a biomarker for perinatal asphyxia, hypothermia-requiring HIE, and poor neurodevelopmental outcome. Confirmatory studies are called for.

Less invasive surfactant administration is associated with a higher need for nonpharmacological pain-relieving interventions compared to the intubation-surfactant extubation technique in preterm infants.

Aim: LISA is a promising method in improving preterm outcome. The aim of this study was to assess whether the INSURE (intubation-surfactant extubation) technique or LISA (less invasive surfactant administration) procedure for surfactant administration is associated with more pain-relieving interventions after the intervention in preterm infants. Methods: Preterm infants born at <32 weeks gestational age admitted to the Neonatal Intensive Care Unit of Innsbruck University hospital between Jan 2012 and June 2017 subjected to INSURE or LISA were included in the study, which was performed as a retrospective analysis of routinely collected data. Pain assessments were made bedside using the Bernese Pain Scale for Neonates. Results: During the study period 15 preterm infants (median gestational age 30.7 weeks; range: 25.9-32.0 weeks) were subjected to INSURE technique and 59 (median gestational age 29.4 weeks; range: 25.1-31.4 weeks) to LISA. Infants subjected to LISA showed a higher need for nonpharmacological pain-relieving interventions in the first three days of life. Conclusion: LISA procedure compared to INSURE technique was associated with a higher need for pain-relieving interventions in the first three days of life. Prospective randomized controlled trials are needed to optimize this less invasive method for surfactant application with special focus on pain in neonates.

The effect of levomepromazine on the healthy and injured developing mouse brain - An in vitro and in vivo study.

Levomepromazine (LMP) is a phenothiazine neuroleptic drug with strong analgesic and sedative properties that is increasingly used off-label in pediatrics and is being discussed as an adjunct therapy in neonatal intensive care. Basic research points towards neuroprotective potential of phenothiazines, but LMP's effect on the developing brain is currently unknown. The aim of the present study was to assess LMP as a pharmacologic strategy in established neonatal in vitro and in vivo models of the healthy and injured developing mouse brain. In vitro, HT-22 cells kept exposure-naïve or injured by glutamate were pre-treated with vehicle or increasing doses of LMP and cell viability was determined. In vivo, LMP's effects were first assessed in 5-day-old healthy, uninjured CD-1 mouse pups receiving a single intraperitoneal injection of vehicle or different dosages of LMP. In a second step, mouse pups were subjected to excitotoxic brain injury and subsequently treated with vehicle or LMP. Endpoints included somatometric data as well as histological and immunohistochemical analyses. In vitro, cell viability in exposure-naïve cells was significantly reduced by high doses of LMP, but remained unaffected in glutamate-injured cells. In vivo, no specific toxic effects of LMP were observed neither in healthy mouse pups nor in experimental animals subjected to excitotoxic injury, but body weight gain was significantly lower following higher-dose LMP treatment. Also, LMP failed to produce a neuroprotective effect in the injured developing brain. Additional studies are required prior to a routine clinical use of LMP in neonatal intensive care units.

Excitotoxicity Alters Endogenous Secretoneurin Plasma Levels, but Supplementation with Secretoneurin Does Not Protect Against Excitotoxic Neonatal Brain Injury.

Excitotoxicity plays an important role in the pathogenesis of developing brain injury. The neuropeptide secretoneurin (SN) has neuroprotective potential. The aim of this study was to investigate SN plasma concentrations following excitotoxicity and to evaluate the effect of SN as therapeutic strategy in excitotoxic newborn brain injury. Baseline SN plasma concentrations were established in healthy animals. To evaluate the effect of an excitotoxic insult on SN levels, mice pups were subjected to an intracranial injection of ibotenic acid and SN plasma concentrations were measured thereafter. To assess SN's neuroprotective potential, a subgroup of animals was randomly assigned to the following groups: i) "single treatment": vehicle 1× phosphate-buffered saline (PBS), SN 0.25 µg/g body weight (bw), SN 2.5 µg/g bw or SN 12.5 µg/g bw in a single dose 1 h after insult; ii) "acute repetitive treatment": vehicle 1× PBS or SN 0.25 µg/g bw every 24 h starting 1 h after insult; iii) "delayed repetitive treatment": vehicle 1× PBS or SN 0.25 µg/g bw every 24 h starting 60 h after insult. Animals subjected to excitotoxic injury showed significantly lower SN plasma concentrations 6 and 120 h after insult in comparison to healthy controls. Administration of SN did not positively affect lesion size, apoptotic cell death, microglial cell activation or cell proliferation. To conclude, endogenous SN plasma levels are lower in newborn mice subjected to an excitotoxic insult than in healthy controls. Supplementation with SN in various treatment regimens is not neuroprotective in the experimental animal model of excitotoxic newborn brain injury.