Emerging neuroprotective interventions in periventricular leukomalacia - A systematic review of preclinical studies.

INTRODUCTION: Periventricular leukomalacia (PVL) is a result of various antenatal, intrapartum, or postnatal insults to the developing brain and is an important harbinger of cerebral palsy in preterm neonates. There is no proven therapy for PVL. This calls for appraisal of targeted therapies that have been investigated in animal models to evaluate their relevance in a clinical research context. AREAS COVERED: This systematic review identifies interventions that were evaluated in preclinical studies for neuroprotective efficacy against PVL. We identified 142 studies evaluating various interventions in PVL animal models (search method is detailed in section 2). EXPERT OPINION: Interventions that have yielded significant results in preclinical research, and that have been evaluated in a limited number of clinical trials include stem cells, erythropoietin, and melatonin. Many other therapeutic modalities evaluated in preclinical studies have been identified, but more data on their neuroprotective potential in PVL must be garnered before they can be considered for clinical trials. Because most of the tested interventions had only a partial efficacy, a combination of interventions that could be synergistic should be investigated in future preclinical studies. Furthermore, since the nature and pattern of perinatal insults to preterm brain predisposing it to PVL are substantially variable, individualized approaches for the choice of appropriate neuroprotective interventions tailored to different subgroups of preterm neonates should be explored.

Mode of delivery and adverse short- and long-term outcomes in vertex-presenting very preterm born infants: a European population-based prospective cohort study.

OBJECTIVES: To compare mortality, morbidity and neurodevelopment by mode of delivery (MOD) for very preterm births with low prelabour risk of caesarean section (CS). METHODS: The study was a population-based prospective cohort study in 19 regions in 11 European countries. Multivariable mixed effects models and weighted propensity score models were used to estimate adjusted odds ratios (aOR) by observed MOD and the unit's policy regarding MOD. Population: Singleton vertex-presenting live births at 24 + 0 to 31 + 6 weeks of gestation without serious congenital anomalies, preeclampsia, HELLP or eclampsia, antenatal detection of growth restriction and prelabour CS for fetal or maternal indications. RESULTS: Main outcome measures: A composite of in-hospital mortality and intraventricular haemorrhage (grade III/IV) or periventricular leukomalacia. Secondary outcomes were components of the primary outcome, 5 min Apgar score <7 and moderate to severe neurodevelopmental impairment at two years of corrected age. The rate of CS was 29.6% but varied greatly between countries (8.0-52.6%). MOD was not associated with the primary outcome (aOR for CS 0.99; 95% confidence interval [CI] 0.65-1.50) when comparing units with a systematic policy of CS or no policy of MOD to units with a policy of vaginal delivery (aOR 0.88; 95% CI 0.59-1.32). No association was observed for two-year neurodevelopment impairment for CS (aOR 1.15; 95% CI 0.66-2.01) or unit policies (aOR 1.04; 95% CI 0.63-1.70). CONCLUSIONS: Among singleton vertex-presenting live births without medical complications requiring a CS at 24 + 0 to 31 + 6 weeks of gestation, CS was not associated with improved neonatal or long-term outcomes.

Antenatal Corticosteroids and Outcomes in Preterm Twins.

OBJECTIVE: To estimate whether improvement in outcomes from antenatal corticosteroid treatment in extremely and very preterm twins is similar to that observed in singletons, and to investigate whether antenatal corticosteroid treatment has different effects according to chorionicity or birth order. METHODS: This population-based study was based on an analysis of data collected by the Neonatal Research Network of Japan from 2003 to 2015 of neonates weighing 1,500 g or less at birth, from gestational ages of 24 0/7 to 31 6/7 weeks of gestation. After propensity score matching, univariate logistic and interaction analyses were performed to compare short-term (neonatal period) and medium-term (3 years of age) outcomes of the children of mothers who received antenatal corticosteroids with those of children of mothers who did not receive antenatal corticosteroids. We focused on differences between singletons and twins, between monochorionic and dichorionic twins and between the first and second twin. RESULTS: The study comprised 23,502 singletons and 6,546 twins. Antenatal corticosteroid treatment was associated with significant decreased short-term neurologic outcomes in both singletons and twins. However, antenatal corticosteroid treatment was associated with significantly decreased mortality (odds ratio [OR] 0.61; 95% CI 0.53-0.70), respiratory distress syndrome (OR 0.71, 95% CI 0.67-0.76), and cerebral palsy (OR 0.85, 95% CI 0.72-0.99) in singletons but not in twins (OR 0.89, 95% CI 0.68-1.17; OR 0.99, 95% CI 0.87-1.12; and OR 0.82, 95% CI 0.61-1.11, respectively). No association was found between chorionicity and the efficacy of antenatal corticosteroid treatment on outcomes. Further, no association was found between birth order and the efficacy of antenatal corticosteroid treatment on outcomes, except for periventricular leukomalacia and necrotizing enterocolitis (interaction: P=.02 and P=.04, respectively). CONCLUSION: Antenatal corticosteroid treatment in twins was associated with a beneficial effect on short-term neurologic outcomes only, without improvement in other short-term and medium-term outcomes. There was no difference related to chorionicity.

Cumulative effect of evidence-based practices on outcomes of preterm infants born at <29 weeks' gestational age.

BACKGROUND: Extremely preterm infants born at <29 weeks' gestational age are at high risk of death or severe neurological injury. Several individual evidence-based practices have been associated with neuroprotection. OBJECTIVE: The objective of the study was to investigate the cumulative effect of 4 evidence-based practices and their association with death and/or severe neurological injury among infants born at <29 weeks' gestational age. STUDY DESIGN: Observational study of infants born at 230-286 weeks gestational age admitted to neonatal intensive care units participating in the Canadian Neonatal Network from 2015 through 2017. We evaluated 4 practices: antenatal corticosteroids, antenatal MgSO4 for neuroprotection, deferred cord clamping ≥30 seconds, and normothermia on admission. The effect of exposure to 1, 2, 3, and all 4 evidence-based practices compared with none on death and/or severe neurological injury was assessed using multivariable logistic regression models adjusted for patient characteristics. RESULTS: Rate of death and/or severe neurological injury was 20% (873 of 4297) and varied based on exposure to evidence-based practices: none, 34% (54 of 157); 1, 27% (171 of 626); 2, 20% (295 of 1448); 3, 18% (263 of 1448); and all 4, 14% (90 of 618). Significantly lower odds of death and/or severe neurological injury were observed with exposure to antenatal corticosteroids (adjusted odds ratio, 0.52, 95% confidence interval, 0.40-0.69) and deferred cord clamping (adjusted odds ratio, 0.81, 95% confidence interval, 0.68-0.96) but not MgSO4 (adjusted odds ratio, 0.88, 95% confidence interval, 0.72-1.08) or normothermia (adjusted odds ratio, 0.96, 95% confidence interval, 0.79-1.16). Infants exposed to ≥2 evidence-based practices had significantly lower odds of death and/or severe neurological injury than those exposed to no evidence-based practices (adjusted odds ratio, 0.61, 95% confidence interval, 0.43-0.88). CONCLUSION: Among infants born at <29 weeks' gestational age, exposure to at least 2 of the evidence-based practices assessed was associated with decreased odds of death and/or severe neurological injury.

A single-dose indomethacin prophylaxis for reducing perinatal brain injury in extremely low birth weight infants: a non-inferiority analysis.

OBJECTIVE: To evaluate whether rates of perinatal brain injury among extremely low birth weight infants are comparable between two treatments: single-dose indomethacin prophylaxis (SGL-IP) (0.2 mg/kg, given once) vs. standard-dose indomethacin prophylaxis (STD-IP) (0.1 mg/kg/day, 3 days). METHODS: In this retrospective study, the primary outcome was perinatal brain injury (neuro-imaging evidence of intraventricular hemorrhage or periventricular leukomalacia) or death before discharge. A non-inferior efficacy of an SGL-IP regimen compared with a STD-IP regimen was determined by calculating the adjusted difference in the risk of the primary outcome using a multivariable logistic regression model. A 10-percentage point non-inferiority margin was favored. RESULTS: Prevalence rates of primary outcome were 41.7% in the SGL-IP group (n = 403) and 42.5% in the STD-IP group (n = 509) (adjusted risk difference: -1.2, 95% CI: -7.6 to +5.2, p = 0.71). CONCLUSION: Use of a single prophylactic indomethacin dose was as effective as a standard regimen in preventing perinatal brain injury.

Pharmacologic Prevention and Treatment of Neonatal Brain Injury.

Neonatal brain injury (NBI) remains a major contributor to neonatal mortality and long-term neurodevelopmental morbidity. Although therapeutic hypothermia is the only proven treatment to minimize brain injury caused by neonatal encephalopathy in term neonates, it provides incomplete neuroprotection. There are no specific drugs yet proven to prevent NBI in preterm neonates. This review discusses the scientific and emerging clinical trial data for several neuroprotective drugs in development, examining potential efficacy and safety concerns. Drugs with the highest likelihood of success and closest to clinical application include erythropoietin for term and preterm neonates and antenatal magnesium for preterm neonates.

Inhibition of microglial activation by minocycline reduced preoligodendrocyte injury in a neonatal rat brain slice model.

BACKGROUND: Periventricular leukomalacia is a common white-matter injury after neonatal cardiac surgery; however, its potential cellular mechanism remains uncertain. There is limited study regarding periventricular leukomalacia treatment. METHODS: A neonatal rat brain slice perfusion model was used for reproducing the condition of cardiopulmonary bypass, and oxygen glucose deprivation simulated circulatory arrest. Seven-day-old Sprague-Dawley rats were randomly divided into 7 groups: (1) control group with 36°C; (2) 60 minutes of oxygen glucose deprivation group on 15°C, 25°C, 36°C, respectively; and (3) 60 minutes of oxygen glucose deprivation group on 15°C, 25°C, 36°C, plus minocycline (10 µmol/L), respectively. Immunohistochemistry, Western blot, and inflammatory mediators were compared after the perfusion procedures in the different groups. RESULTS: This neonatal rat brain slice perfusion with oxygen glucose deprivation model could replicate the pathophysiologic process and injury after cardiopulmonary bypass and hypothermic circulatory arrest. With the increase of oxygen glucose deprivation perfusion temperature, we found that both microglia activation and preoligodendrocyte loss increased. The application of minocycline can significantly inhibit microglial activation and preoligodendrocyte cells loss in the normothermic (36°C) and moderate hypothermia (25°C) oxygen glucose deprivation groups (P < .05), with accompanying significant decreasing microglial inflammatory productions; however, no significant improvement was found in the deep hypothermia (15°C) group. CONCLUSIONS: The microglial activation may play a key role in preoligodendrocyte injury in the ex vivo neonatal rat brain slice perfusion and circulatory arrest model. Inhibition of microglial activation with minocycline may be an attractive target for white-matter protection during cardiopulmonary bypass and hypothermic circulatory arrest.

Perinatal Brain Injury: Mechanisms, Prevention, and Outcomes.

Perinatal brain injury may lead to long-term morbidity and neurodevelopmental impairment. Improvements in perinatal care have resulted in the survival of more infants with perinatal brain injury. The effects of hypoxia-ischemia, inflammation, and infection during critical periods of development can lead to a common pathway of perinatal brain injury marked by neuronal excitotoxicity, cellular apoptosis, and microglial activation. Various interventions can prevent or improve the outcomes of different types of perinatal brain injury. The objective of this article is to review the mechanisms of perinatal brain injury, approaches to prevention, and outcomes among children with perinatal brain injury.

Pretreatment with magnesium sulfate attenuates white matter damage by preventing cell death of developing oligodendrocytes.

AIM: Antenatal maternal administration of magnesium sulfate (MgSO4 ) reduces cerebral palsy in preterm infants. However, it remains controversial as to whether it also reduces occurrence of white matter damage, or periventricular leukomalacia. We assessed the effect of MgSO4 against white matter damage induced by hypoxic-ischemic insult using a neonatal rat model and culture of premyelinating oligodendrocytes (pre-OL). METHODS: Rat pups at postnatal day (P) 6 were administered either MgSO4 or vehicle intraperitoneally before hypoxic-ischemic insult (unilateral ligation of the carotid artery followed by 6% oxygen for 1 h). The population of oligodendrocyte (OL) markers and CD-68-positive microglia at P11, and TdT-mediated biotin-16-dUTP nick-end labeling (TUNEL)-positive cells at P8 were evaluated in pericallosal white matter. Primary cultures of mouse pre-OL were subjected to oxygen glucose deprivation condition, and the lactate dehydrogenase release from culture cells was evaluated to assess cell viability. RESULTS: Pretreatment with MgSO4 attenuated the loss of OL markers, such as myelin basic protein and Olig2, in ipsilateral pericallosal white matter and decreased the number of CD-68-positive microglia and TUNEL-positive cells in vivo. Pretreatment with MgSO4 also inhibited lactate dehydrogenase release from pre-OL induced by oxygen glucose deprivation in vitro. CONCLUSION: Pretreatment with MgSO4 attenuates white matter damage by preventing cell death of pre-OL.

Antenatal corticosteroids in impending preterm deliveries before 25 weeks' gestation.

Antenatal corticosteroid (ANC) use before 25 weeks' gestation is controversial. Our previous systematic review (eight observational studies, n=10 109) showed that ANC exposure was associated with significantly reduced mortality and severe intraventricular haemorrhage (IVH)/periventricular leukomalacia (PVL) in neonates born <25 weeks. We update our review by adding data (n=3334) from a recent study. We used Cochrane methodology and summarised the results using GRADE (The Grading of Recommendations Assessment, Development and Evaluation) guidelines. Nine high-quality observational studies were included. Meta-analysis (random effects model) showed reduced mortality (n=13 443; OR=0.48 (95% CI 0.42 to 0.55) P<0.00001; level of evidence (LOE): moderate) and IVH or PVL (n=8418; OR=0.70 (95% CI 0.63 to 0.79), P<0.00001; LOE: moderate) in neonates born <25 weeks exposed to ANC. There was no difference in necrotising enterocolitis (NEC) ≥stage II (n=8737; OR=1.01 (95% CI 0.84 to 1.22), P=0.89; LOE: low); incidence of chronic lung disease (CLD) was higher (n=7983; OR=1.32 (95% CI 1.04 to 1.67), P=0.02; LOE: low) in ANC group. Composite outcomes of death/major morbidities (eg, severe IVH, NEC, CLD) were improved after ANC exposure.

Efficacy of antenatal corticosteroids in preterm twins: the EPIPAGE-2 cohort study.

OBJECTIVES: To investigate the efficacy of antenatal corticosteroid (ACS) therapy on short-term neonatal outcomes in preterm twins, and further document the influence of the ACS-to-delivery interval. DESIGN: EPIPAGE-2 is a nationwide observational multicentre prospective cohort study of neonates born between 22 and 34 completed weeks of gestation. SETTING: All French maternity units, except in a single administrative region, between March and December 2011. POPULATION: A total of 750 twin neonates born between 24 and 31 weeks of gestation. METHODS: Exposure to ACSs was examined in four groups: single complete course, with an ACS administration-to-delivery interval of ≤7 days; single complete course, with an ACS-to-delivery interval of >7 days; repeated courses; or no ACS treatment. MAIN OUTCOME MEASURES: Neonatal outcomes analysed were severe bronchopulmonary dysplasia, periventricular leukomalacia or intraventricular haemorrhage grade III/IV, in-hospital mortality, and a composite indicator of severe outcomes. RESULTS: Compared with no ACSs, in multivariable analysis, a single course of ACSs with an administration-to-delivery interval of ≤7 days was significantly associated with a reduced rate of periventricular leukomalacia or intraventricular haemorrhage grade III/IV (aOR 0.2; CI 95% 0.1-0.5), in-hospital mortality (0.3; 0.1-0.6), and the composite indicator (0.1; 0.1-0.3), whereas a single course of ACDs with an administration-to-delivery interval of >7 days did not significantly reduce the frequency of in-hospital mortality (0.7; 0.3-1.8). No significant differences in terms of benefit or risk were found when comparing repeated courses with a single complete course. CONCLUSION: In preterm twins, a single complete course of antenatal corticosteroids was associated with an improvement of severe neurological outcome, whereas reduced in-hospital mortality was seen only when the ACS-to-delivery interval was ≤7 days. TWEETABLE ABSTRACT: A single complete course of antenatal steroids reduced severe neurological morbidity in preterm twins (24-31 weeks).

Reducing tobacco smoking and smoke exposure to prevent preterm birth and its complications.

Tobacco smoking and smoke exposure during pregnancy are associated with a range of adverse health outcomes, including preterm birth. Also, children born preterm have a higher risk of complications including bronchopulmonary dysplasia and asthma when their mothers smoked during pregnancy. Smoking cessation in early pregnancy can help reduce the adverse impact on offspring health. Counselling interventions are effective in promoting smoking cessation and reducing the incidence of preterm birth. Peer support and incentive-based approaches are likely to be of additional benefit, whereas the effectiveness of pharmacological interventions, including nicotine replacement therapy, has not definitely been established. Smoke-free legislation can help reduce smoke exposure as well as maternal smoking rates at a population level, and is associated with a reduction in preterm birth. Helping future mothers to stop smoking and protect their children from second hand smoke exposure must be a key priority for health care workers and policy makers alike.

Ibuprofen and indomethacin for the closure of the patent ductus arteriosus / Ibuprofen, indometacina e fechamento do canal arterial

The ductus arteriosus connects the pulmonary artery with the aorta and allows right ventricular blood to bypass the unexpanded lungs. In mature infants, the ductus arteriosus closes after birth. Patent ductus arteriosus occurs in 70% of preterm infants with a birth weight < 1,000 grams. Failure of the ductus arteriosus to close has been associated with intraventricular hemorrhage, necrotizing enterocolitis, bronchopulmonary dysplasia, periventricular leukomalacia, renal failure, and persistent pulmonary hypertension. The drugs used to treat the patent ductus arteriosus are ibuprofen and indomethacin which are potent non-selective inhibitors of cyclo-oxygenase (COX) and therefore inhibit prostaglandin E2 synthesis. Prostaglandin E2 relaxes smooth muscle and tends to inhibit the closure of the patent ductus arteriosus. Intravenous ibuprofen and indomethacin inhibit prostaglandin E2 synthesis and thereby close the patent ductus arteriosus with similar efficacy. Indomethacin reduces the blood flow velocity in kidneys, intestine and brain. Ibuprofen has less effect on blood flow velocity in these organs. There is a significant increase in serum creatinine after indomethacin administration but not after ibuprofen and infants treated with ibuprofen have higher creatinine clearance. Oliguria (urine output < 1 ml/kg/h) occurs more frequently with indomethacin than with ibuprofen. Indomethacin requires furosemide for urine output more often than ibuprofen. Ibuprofen reduces the risk of necrotizing enterocolitis and transient renal insufficiency and it is the drug of choice for closing the patent ductus arteriosus. Ibuprofen and indomethacin may be administered orally. In conclusion, intravenous ibuprofen and indomethacin close the patent ductus arteriosus at the same rate, but indomethacin is more toxic than ibuprofen.

O canal arterial conecta a artéria pulmonar com a aorta e permite que o sangue oriundo do ventrículo direito evite passar pelos pulmões fetais não expandidos. Em recém-nascidos maduros, o canal arterial se fecha após o nascimento. A persistência do canal arterial ocorre em 70% dos recém-nascidos prematuros com peso de nascimento < 1.000 gramas. O não fechamento do canal arterial associa-se a hemorragia intraventricular, enterocolite necrosante, displasia bronco-pulmonar, leucomalacia periventricular, insuficiência renal e hipertensão pulmonar persistente. Os medicamentos utilizados para tratar a persistência do canal arterial são o ibuprofeno e a indometacina. Ambos são potentes inibidores não seletivos da ciclo-oxigenase e inibem a síntese de prostaglandina E2. Esta relaxa a musculature vascular lisa e tende a inibir o fechamento do canal arterial. O ibuprofeno e a indometacina inibem a síntese de prostaglandina E2 e favorecem o fechamento do canal arterial. A indometacina reduz a velocidade do fluxo sanguíneo renal, intestinal e cerebral. O Ibuprofeno tem efeito menor sobre a velocidade do fluxo de sangue nesses órgãos. Há um aumento significativo da creatinina sérica após a administração de indometacina, mas não após o ibuprofeno; por isso, recém-nascidos tratados com ibuprofeno têm maior depuração da creatinina. A oligúria ocorre mais frequentemente com a indometacina vs. ibuprofeno. A indometacina requer furosemida para a produção de urina mais frequentemente do que o ibuprofeno. O ibuprofeno reduz o risco de enterocolite necrotizante e de insuficiência renal transitória e é a droga de escolha para o fechamento do canal arterial patente. O ibuprofeno e a indometacina podem ser ministrados por via oral. Em conclusão, o ibuprofeno e a indometacina fecham o canal arterial patente com a mesma velocidade, mas a indometacina é mais tóxica.

Association Between Antenatal Corticosteroid Administration-to-Birth Interval and Outcomes of Preterm Neonates.

OBJECTIVE: To assess the association between antenatal corticosteroid administration-to-birth interval and outcomes. METHODS: In this retrospective cohort study, data on singleton neonates born between 24 0/7 and 33 6/7 weeks of gestation and admitted to tertiary neonatal units in Canada during 2010-2012 were obtained from the Canadian Neonatal Network. Neonatal outcomes were compared among four groups based on the interval between antenatal corticosteroid administration and birth: no antenatal corticosteroids, partial antenatal corticosteroids (less than 24 hours before birth), antenatal corticosteroids 1-7 days before birth, and antenatal corticosteroids greater than 7 days before birth. Composite outcome was defined as any of neonatal mortality, bronchopulmonary dysplasia, grade 3-4 intraventricular hemorrhage, periventricular leukomalacia, or stage 3 or higher retinopathy. RESULTS: Of 6,870 eligible neonates, 1,378 (20%) received no antenatal corticosteroids; 1,473 (21%) received partial antenatal corticosteroids; 2,721 (40%) received antenatal corticosteroids 1-7 days before birth; and 1,298 (19%) received antenatal corticosteroids greater than 7 days before birth. The odds of the composite adverse outcome were significantly higher in all groups compared with neonates who received antenatal corticosteroids 1-7 days before birth (no antenatal corticosteroids: adjusted odds ratio [OR] 2.12, 95% confidence interval [CI] 1.69-2.65; partial antenatal corticosteroids: adjusted OR 1.48, 95% CI 1.22-1.80; and antenatal corticosteroids at greater than 7 days: adjusted OR 1.46, 95% CI 1.20-1.77). Similar findings were observed with respect to neonatal mortality (no antenatal corticosteroids: adjusted OR 2.56, 95% CI 1.83-3.59; partial antenatal corticosteroids: adjusted OR 1.59, 95% CI 1.16-2.18; and antenatal corticosteroids at greater than 7 days: adjusted OR 1.40, 95% CI 1.00-1.97). CONCLUSION: Antenatal corticosteroids had maximum benefit when given between 1 and 7 days before birth. LEVEL OF EVIDENCE: II.

Oxygen administration to preterm neonates in the delivery room: minimizing oxidative stress.

BACKGROUND: Neonatal resuscitation continues to be challenged by evolving research on the best approach to resuscitating preterm infants while minimizing potential health risks. The actions of the resuscitation team in the first minutes of transition to extrauterine life can have a lasting impact on the growth and development of the preterm infant. PURPOSE: This article reviews the most current literature on the use of oxygen in the delivery room and discusses the implications related to nursing and the multidisciplinary care team. FINDINGS: Oxygen saturation monitoring in the delivery room through the use of pulse oximetry in conjunction with oxygen titration via a blended oxygen source is an appropriate intervention to decrease the risk of free radical damage to the tissues. IMPLICATIONS FOR PRACTICE: Ensure delivery room providers are educated to resuscitation standards and ensure delivery rooms are appropriately supplied with a compressed air source, oxygen blenders, and pulse oximeters to minimize the free radical damage to the tissues. IMPLICATIONS FOR RESEARCH: Future studies should be focused on pulse oximetry use in the delivery room and its effect on long-term outcomes for preterm infants, safe oxygen saturation target ranges for the preterm infant in the delivery room, and effective resuscitation procedures for extremely preterm infants.

Chloride cotransporter NKCC1 inhibitor bumetanide protects against white matter injury in a rodent model of periventricular leukomalacia.

BACKGROUND: Periventricular leukomalacia (PVL) is a major form of preterm brain injury. Na(+)-K(+)-Cl(-) 1 cotransporter (NKCC1) expression on neurons and astrocytes is developmentally regulated and mediates Cl(-) reversal potential. We hypothesized that NKCC1 is highly expressed on oligodendrocytes (OLs) and increases vulnerability to hypoxia-ischemia (HI) mediated white matter injury, and that the NKCC1 inhibitor bumetanide would be protective in a rodent PVL model. METHODS: Immunohistochemistry in Long-Evans rats and PLP-EGFP transgenic mice was used to establish cell-specific expression of NKCC1 in the immature rodent brain. HI was induced on postnatal day 6 (P6) in rats and the protective efficacy of bumetanide (0.3 mg/kg/i.p. q12h × 60 h) established. RESULTS: NKCC1 was expressed on OLs and subplate neurons through the first 2 postnatal weeks, peaking in white matter and the subplate between P3-7. Following HI, NKCC1 is expressed on OLs and neurons. Bumetanide treatment significantly attenuates myelin basic protein loss and neuronal degeneration 7 d post-HI. CONCLUSION: Presence and relative overexpression of NKCC1 in rodent cerebral cortex coincides with a period of developmental vulnerability to HI white matter injury in the immature prenatal brain. The protective efficacy of bumetanide in this model of preterm brain injury suggests that Cl(-) transport is a factor in PVL and that its inhibition may have clinical application in premature human infants.

Association of antenatal corticosteroids and the mode of delivery with the mortality and morbidity of infants weighing less than 1,500g at birth in Japan.

OBJECTIVE: This study aimed to re-evaluate the effectiveness of antenatal corticosteroids (ACS) and to analyze the association between ACS and the mode of delivery in the context of perinatal morbidity and mortality in very-low-birth-weight (VLBW) infants. STUDY DESIGN: This retrospective cohort study involved 15,765 VLBW infants born between 2003 and 2008 at less than 34 weeks of gestation and weighing less than 1,500 g at birth. Data were obtained from the Japanese neonatal research network database. Univariate and multivariate logistic regression analyses were performed to evaluate the impact of ACS and mode of delivery on the risk of infant mortality and morbidity. RESULTS: Administration of ACS was associated with decreases in mortality rate, intraventricular hemorrhage (IVH) and retinopathy of prematurity (ROP), and was not associated with the incidence of respiratory distress syndrome (RDS), periventricular leukomalacia or necrotizing enterocolitis (NEC). When the administration of ACS was analyzed in the context of different modes of delivery, the incidence of IVH and ROP tended to decrease with cesarean section deliveries, whereas the incidence of RDS tended to decrease and the incidence of NEC tended to increase for infants delivered vaginally. The incidence of chronic lung disease tended to increase in association with both delivery methods. CONCLUSIONS: This large cohort study reconfirms that ACS treatment is associated with decreases in infant mortality and severe morbidity. Furthermore, the delivery method may be associated with severe morbidity in VLBW infants exposed to ACS.

Repetitive administration of acetylcholine receptor agonist rescues brain inflammation and brain damage after hypoxia-ischemia in newborn rat.

OBJECTIVE: We examined the effect of repetitive administration of acetylcholine receptor agonist (carbachol) on brain damage and microglial accumulation in three brain regions after hypoxia-ischemia (HI) in newborn rat. STUDY DESIGN: Seven-day-old Wistar rats were divided into two groups, one receiving a 0.1 mg/kg dose of carbachol on days 7, 8 and 9 to examine the attenuating effect on brain damage with decreasing accumulation of microglia, and the other group receiving saline as a control. Rats were subjected to left carotid artery ligation followed by hypoxia. We evaluated brain damage and the number of microglias in three regions on days 10 and 14. RESULTS: Brain tissue was better preserved in the carbachol group on days 10 and 14. Microglial accumulation in the cortex was strong and persisted from day 10s to 14 in the control. Conversely, the accumulation of microglias was attenuated in the hippocampus and white matter on day 14. Carbachol significantly reduced the number of microglias in the hippocampus and white matter on day 10 and in the cortex on days 10 and 14. CONCLUSION: The main area of late inflammation was the cortex. Repetitive administration of carbachol reduces early and late inflammation after HI in the developing brain.

Zinc supplementation reduces morbidity and mortality in very-low-birth-weight preterm neonates: a hospital-based randomized, placebo-controlled trial in an industrialized country.

BACKGROUND: Zinc plays a pivotal role in the pathogenesis of many diseases and in body growth. Preterm neonates have high zinc requirements. OBJECTIVE: The objective of the study was to investigate the efficacy of zinc supplementation in reducing morbidity and mortality in preterm neonates and to promote growth. DESIGN: This was a prospective, double-blind, randomized controlled study of very-low-birth-weight preterm neonates randomly allocated on the seventh day of life to receive (zinc group) or not receive (control group) oral zinc supplementation. Total prescribed zinc intake ranged from 9.7 to 10.7 mg/d in the zinc group and from 1.3 to 1.4 mg/d in the placebo control group. The main endpoint was the rate of neonates with ≥ 1 of the following morbidities: late-onset sepsis, necrotizing enterocolitis, bronchopulmonary dysplasia, periventricular leucomalacia, and retinopathy of prematurity. Secondary outcomes were mortality and body growth. RESULTS: We enrolled 97 neonates in the zinc group and 96 in the control group. Morbidities were significantly lower in the zinc group (26.8% compared with 41.7%; P = 0.030). The occurrence of necrotizing enterocolitis was significantly higher in the control group (6.3% compared with 0%; P = 0.014). Mortality risk was higher in the placebo control group (RR: 2.37; 95% CI: 1.08, 5.18; P = 0.006). Daily weight gain was similar in the zinc (18.2 ± 5.6 g · kg⁻¹ · d⁻¹) and control (17.0 ± 8.7 g · kg⁻¹ · d⁻¹) groups (P = 0.478). CONCLUSION: Oral zinc supplementation given at high doses reduces morbidities and mortality in preterm neonates. This trial was registered in the Australian New Zealand Clinical Trial Register as ACTRN12612000823875.

White matter injury in preterm infants: could human milk play a role in its prevention?

Human milk has been found to be beneficial for the development of all newborns. It is protective during the development of the gastrointestinal tract, important in neurologic development, immune system function, and nourishment. Human milk has a number of components that aid in the anti-inflammatory process and free radical reduction and is a building block for neurologic development. Cerebral white matter injury is a common occurrence in preterm infants. Results of this injury can be seen into early childhood and throughout the life of the individual. White matter injury most frequently occurs because of hypoxia and the inflammatory process, which often results in the injury of myelinating oligodendrites. This article proposes the potential importance of human milk in slowing and preventing cerebral white matter injury because of the components in human milk that affect the inflammatory and free radical reduction processes. It also proposes its ability to provide nutrients essential to myelin development.