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.

Dietary treatment of congenital chylothorax with skimmed breast milk.

BACKGROUND: Congenital chylothorax (CC) is a rare but potentially life-threatening condition in newborns. It is defined as an accumulation of chyle in the pleural cavity. The few publications regarding medical management and therapeutic dietary intervention motivated us to share our experience. METHODS: Neonates diagnosed with congenital chylothorax and treated at Innsbruck Medical University Hospital between 2013 and 2020 (n = 6, gestational age: 36 3/7, 32 5/7, 36 4/7, 35 0/7, 35 4/7, 37 3/7 weeks) were eligible for this report. The cornerstones of treatment for chylothorax conventionally consist of chest tube drainage (CTD), respiratory support, dietary restriction of long-chain triglycerides (LCT) or total parenteral nutrition (TPN). In further course the introduction of a medium-chain triglyceride (MCT)-based formula followed by an overlapping switch to a formula with low LCT and high MCT, containing the essential long-chain fatty acids (LCFA), is attempted. In three patients we used fat-modified (skimmed) breast milk to provide a high protein and low fat diet and to avoid the discontinuation of breast milk. RESULTS: The outcome of an early introduction of LCFA in the form of skimmed breast milk after resolution of chylothorax diverse. One patient had a favourable outcome, meaning no recurrence of pleural effusion, adequate weight gain and a content mother, while another patient had a relapse of pleural effusion after the administration of skimmed milk and was therefore transitioned back to Basic F® . The CC of patient 5 was difficult due to Noonan syndrome. Two weeks after the introduction of skimmed breast milk the mother wanted to stop to express breast milk, so nutrition was changed to Basic F®. CONCLUSION: The first-line therapy of chylothorax is a combination of respiratory stabilization and dietary modification. The use of skimmed breast milk is advisable in CC and feasible by means of a simple milk defatting procedure. It offers benefits to mothers who wish to resume breast feeding after resolution of chylothorax and has proven positive effects, above all in preterm infants as optimal nutrition with protective components superior to formula feeding. However, the nutritional analysis of the skimmed milk and the correlation to a re-accumulation of pleural fluid remains a question to be answered.

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.

Administration of secretoneurin is protective in hypoxic-ischemic neonatal brain injury predominantly in the hypoxic-only hemisphere.

Neonatal brain injury is a problem of global importance. To date, no causal therapies are available. A substance with considerable therapeutic potential is the endogenous neuropeptide secretoneurin (SN), which has proven to be beneficial in adult stroke. The aim of this study was to assess its effect in neonatal hypoxic-ischemic brain injury models. In vitro, primary hippocampal neurons were pre-treated with vehicle, 1µg/ml, 10µg/ml, or 50µg/ml SN and subjected to oxygen-glucose deprivation (OGD) for six hours. Cell death was assessed after a 24-h recovery period. In vivo, seven day-old CD-1 mice underwent unilateral common carotid artery ligation and were exposed to 8% oxygen/nitrogen for 20 min. SN plasma concentrations were serially determined by ELISA after insult. One hour after hypoxia, a subgroup of animals was treated with vehicle or SN. SN plasma concentrations significantly decreased 48h after insult. The number of caspase-3-positive cells was significantly lower in the hypoxic-ischemic hemisphere in the thalamus of SN-treated animals. In the hypoxic-only hemisphere administration of SN significantly reduced the number of caspase-3-positive cells (in cortex, white matter, hippocampus, thalamus and striatum) and inhibited microglial cell activation in the thalamus. SN has neuroprotective potential in neonatal brain injury. Its main action seems to be inhibition of apoptosis in the aftermath of the insult, predominantly in the hypoxic-only hemisphere. This might be explained by the less pronounced injury in this hemisphere, where blood flow and thus nutrient supply are maintained.

Secretoneurin Serum Levels in Healthy Term Neonates and Neonates with Hypoxic-Ischaemic Encephalopathy.

BACKGROUND: Hypoxic-ischaemic encephalopathy is a major cause of neurologic impairment and mortality in neonates. Early knowledge of brain injury is important to guide therapeutic decisions and reliably inform the parents. Increased secretoneurin levels have been detected in adult patients suffering from brain injury and it has also been shown to be a promising early serum biomarker of unfavourable neurological outcome. However, no data are available in neonates. OBJECTIVE: The aim of this study was to obtain reference values for secretoneurin in healthy term neonates and then to assess the potential of this neuropeptide as a biomarker in the context of hypoxic-ischaemic encephalopathy in asphyxiated term neonates. METHODS: A total number of 139 term neonates, of which 7 were asphyxiated and 132 were healthy, were prospectively enrolled. Secretoneurin serum concentrations were assessed by radioimmunoassay. RESULTS: In healthy controls, secretoneurin serum concentrations were influenced by the mode of delivery (highest in infants born per vacuum extraction and lowest in infants born per caesarean section) and abnormal cardiotocography. In asphyxiated term neonates, secretoneurin concentrations were higher in umbilical cord blood and significantly lower 48 h after birth in comparison to healthy controls. CONCLUSION: Secretoneurin levels are elevated in cord blood in infants suffering from hypoxic-ischaemic encephalopathy following perinatal asphyxia. The potential of secretoneurin as a marker of neonatal hypoxic-ischaemic brain injury should be further evaluated in larger trials.

Delayed application of the haematopoietic growth factors G-CSF/SCF and FL reduces neonatal excitotoxic brain injury.

BACKGROUND: Developmental brain injury results in cognitive and motor deficits in the preterm infant. Enhanced glutamate release and subsequent receptor activation are major pathogenetic factors. The effect of haematopoietic growth factors, such as granulocyte colony-stimulating factor (G-CSF), stem cell factor (SCF) and flt-3 ligand (FL) on neonatal brain injury is controversially discussed. Timing of treatment is known to be a crucial factor. Based on the hypothesis that an exacerbation of injury is caused by administration of substances in the acute phase, the objective of this study was to evaluate the effect of delayed administration of G-CSF/SCF and FL to protect against excitotoxic brain injury in vivo. METHODS: In an established neonatal mouse model of excitotoxic brain injury, we evaluated the effect of daily intraperitoneal doses of G-CSF/SCF or FL, starting 60 h after the excitotoxic insult. RESULTS: Intraperitoneal injections of G-CSF/SCF and FL, given 60 h after the excitotoxic insult, significantly reduced lesion size at postnatal days 10, 18 and 90. G-CSF/SCF treatment resulted in a decrease in apoptotic cell death indicated by reduced caspase-3 activation. G-CSF/SCF and FL treatment did not affect apoptosis-inducing factor-dependent apoptosis or cell proliferation. CONCLUSION: We show that delayed systemic treatment with the haematopoietic growth factors G-CSF/SCF and FL protects against N-methyl-D-aspartate receptor-mediated developmental excitotoxic brain damage. Our results suggest that neuroprotective effects in this neonatal animal model of excitotoxic brain injury depend on the timing of drug administration after the insult.

The sigma-1 receptor agonist 4-phenyl-1-(4-phenylbutyl) piperidine (PPBP) protects against newborn excitotoxic brain injury by stabilizing the mitochondrial membrane potential in vitro and inhibiting microglial activation in vivo.

Premature birth represents a clinical situation of risk for brain injury. The diversity of pathophysiological processes complicates efforts to find effective therapeutic strategies. Excitotoxicity is one important factor in the pathogenesis of preterm brain injury. The observation that sigma-1 receptor agonists possess neuroprotective potential, at least partly mediated by a variety of anti-excitotoxic mechanisms, has generated great interest in targeting those receptors to counteract brain injury. The objective of this study was to evaluate the effect of the highly specific sigma-1 receptor agonist, 4-phenyl-1-(4-phenylbutyl) piperidine (PPBP) to protect against excitotoxic developmental brain injury in vivo and in vitro. Primary hippocampal neurons were pre-treated with PPBP before glutamate was applied and subsequently analyzed for cell death (PI/calcein AM), mitochondrial activity (TMRM) and morphology of the neuronal network (WGA) using confocal microscopy. Using an established neonatal mouse model we also determined whether systemic injection of PPBP significantly attenuates excitotoxic brain injury. PPBP significantly reduced neuronal cell death in primary hippocampal neurons exposed to glutamate. Neurons treated with PPBP showed a less pronounced loss of mitochondrial membrane potential and fewer morphological changes after glutamate exposure. A single intraperitoneal injection of PPBP given one hour after the excitotoxic insult significantly reduced microglial cell activation and lesion size in cortical gray and white matter. The present study provides strong support for the consideration of sigma-1 receptor agonists as a candidate therapy for the reduction of neonatal excitotoxic brain lesions and might offer a novel target to counteract developmental brain injury.