Cerebral Insufficiency Caused by Diazoxide in a Premature Neonate with Congenital Hyperinsulinism.

Diazoxide is a peripheral vasodilator that has been used for intravenous treatment of hypertensive emergencies. However, it is currently used mainly for hyperinsulinemic hypoglycemia in lower dose orally, and its major side effects are edema and pulmonary hypertension. Herein, we report the first association between periventricular leukomalacia (PVL) and intractable hypotension due to diazoxide. A Japanese female premature infant showed hypoglycemia concomitant with hyperinsulinemia. She was diagnosed with congenital hyperinsulinism, and oral diazoxide was started. Six days after starting diazoxide, she suddenly showed peripheral coldness, oliguria, and severe hypotension. The hypotension was refractory to general vasopressor therapies and persisted even after the discontinuation of diazoxide. Cranial echography showed periventricular echodensities followed by cystic PVL. Low-dose vasopressin effectively treated the hypotension. This single case reminds us the serious adverse events of diazoxide that have been forgotten, especially in premature neonates.

Antenatal dexamethasone before asphyxia promotes cystic neural injury in preterm fetal sheep by inducing hyperglycemia.

Antenatal glucocorticoid therapy significantly improves the short-term systemic outcomes of prematurely born infants, but there is limited information available on their impact on neurodevelopmental outcomes in at-risk preterm babies exposed to perinatal asphyxia. Preterm fetal sheep (0.7 of gestation) were exposed to a maternal injection of 12 mg dexamethasone or saline followed 4 h later by asphyxia induced by 25 min of complete umbilical cord occlusion. In a subsequent study, fetuses received titrated glucose infusions followed 4 h later by asphyxia to examine the hypothesis that hyperglycemia mediated the effects of dexamethasone. Post-mortems were performed 7 days after asphyxia for cerebral histology. Maternal dexamethasone before asphyxia was associated with severe, cystic brain injury compared to diffuse injury after saline injection, with increased numbers of seizures, worse recovery of brain activity, and increased arterial glucose levels before, during, and after asphyxia. Glucose infusions before asphyxia replicated these adverse outcomes, with a strong correlation between greater increases in glucose before asphyxia and greater neural injury. These findings strongly suggest that dexamethasone exposure and hyperglycemia can transform diffuse injury into cystic brain injury after asphyxia in preterm fetal sheep.

Antenatal exposure to indomethacin increases the risk of severe intraventricular hemorrhage, necrotizing enterocolitis, and periventricular leukomalacia: a systematic review with metaanalysis.

OBJECTIVE: The purpose of this study was to provide an updated summary of the literature regarding the effects of tocolysis with indomethacin on neonatal outcome by systematically reviewing previously and recently reported data. STUDY DESIGN: All previously reported studies pertaining to indomethacin tocolysis and neonatal outcomes along with recently reported data were identified with the use of electronic databases that had been supplemented with references that were cited in original studies and review articles. Observational studies that compared neonatal outcomes among preterm infants who were exposed and not exposed to indomethacin were included in this systematic review. Data were extracted and quantitative analyses were performed on those studies that assessed the neonatal outcomes of patients that received antenatal tocolysis with indomethacin. RESULTS: Twenty-seven observational studies that met criteria for systematic review and metaanalysis were identified. These studies included 8454 infants, of whom 1731 were exposed to antenatal indomethacin and 6723 were not exposed. Relative risks with 95% confidence intervals were calculated for dichotomous outcomes with the use of random and fixed-effects models. Metaanalysis revealed no statistically significant differences in the rates of respiratory distress syndrome, patent ductus arteriosus, neonatal mortality rate, neonatal sepsis, bronchopulmonary dysplasia, or intraventricular hemorrhage (all grades). However, antenatal exposure to indomethacin was associated with an increased risk of severe intraventricular hemorrhage (grade III-IV based on Papile's criteria; relative risk, 1.29; 95% confidence interval, 1.06-1.56), necrotizing enterocolitis (relative risk, 1.36; 95% confidence interval, 1.08-1.71), and periventricular leukomalacia (relative risk, 1.59; 95% confidence interval, 1.17-2.17). CONCLUSION: The use of indomethacin as a tocolytic agent for preterm labor is associated with an increased risk for severe intraventricular hemorrhage, necrotizing enterocolitis, and periventricular leukomalacia.

The expression profile of microRNAs in wistar rats with lipopolysaccharide-induced periventricular leukomalacia.

Over the recent decades, with numbers of premature infants being cured, clinical diseases on brain damage like periventricular leukomalacia (PVL) have become much more common. Meanwhile, since the discovery of first miRNA lin-4, an increasing number of important studies about this small RNA have been performed not only in the normal organ development but also in the pathogenic mechanism of diseases. However, throughout the past several years, there have been rare miRNA researches discussing the connection between the PVL and miRNA. In view of this situation, we constructed an animal model of PVL induced by lipopolysaccharide (LPS) and performed a miRNA microarray which was repeated three times to profile the expression of microRNAs (miRNAs) between two groups (PVL group versus control group). Then, miRNAs with notable fold changes (fold change >1.5) were found; some of them were further validated by real-time PCR. As a result, 104 differentially expressed miRNAs were identified using the microarray, including 64 upregulated and 40 downregulated miRNAs. Then, five miRNAs of them were selected, characterized by consistent trend in expression in all three microarrays. Among these five miRNAs (miRNA-451, miRNA-200b, miRNA-29a, miRNA-21, and miRNA-138), we subsequently selected miRNA-451 and miRNA-200b for real-time PCR because they possess the highest fold changes. Finally, the results of PCR are basically in accord with the microarray. We guess these new identified miRNAs may play an important role in the pathogenesis of PVL and may provide certain pathophysiological basis for the future research of related diseases in preterm infants.

Intracerebral lipopolysaccharide induces neuroinflammatory change and augmented brain injury in growth-restricted neonatal rats.

INTRODUCTION: Intrauterine growth restriction (IUGR) alters fetal development and is associated with neurodevelopmental abnormalities. We hypothesized that growth restriction from reduced intrauterine perfusion would predispose neonatal rats to subsequent inflammatory brain injury. METHODS: In this study, IUGR was achieved by induced placental insufficiency in pregnant rats at 14 days of gestation. IUGR offspring and sham-operated control pups were subsequently injected with intracerebral lipopolysaccharide (LPS) as a model of periventricular leukomalacia (PVL). RESULTS: LPS similarly elevates proinflammatory cytokines in the brains of both IUGR and control rat pups. However, the chemokines cytokine-induced neutrophil chemoattractant-1 (CINC-1) and macrophage chemoattractant protein-1 (MCP-1), as well as microglia activation, were significantly higher in LPS-treated IUGR rat pups as compared with LPS-treated controls. In addition to the unique brain inflammatory response, IUGR rat pups demonstrated increased brain damage with an increased number of apoptotic cells, larger lateral ventricular size, and more severe impairment of myelination. DISCUSSION: This study provides evidence that placental insufficiency may sensitize the innate immune system in the immature brain and reveals a possible link between brain inflammation and injury.

IGF-1 can either protect against or increase LPS-induced damage in the developing rat brain.

Periventricular leukomalacia (PVL) is a major form of brain damage in premature infants. This study was to test whether IGF-1 can prevent PVL-like brain damage induced by lipopolysaccharide (LPS) in the neonatal rat. Intraventricular delivery of LPS resulted in an acute brain inflammatory response, i.e., rapid recruitment of polymorphonuclear leukocytes (PMNs), activation of microglia and astrocytes, and induction of IL-1beta (IL1beta) expression. Brain inflammation was associated with the loss of O4+ preoligodendrocytes (preOLs), a decrease of myelin basic protein (MBP) in the white matter and an increase of pyknotic cells in the cortex. IGF-1 at a low dose significantly prevented LPS-induced deleterious effects without alteration of IL-1beta expression and microglia/astrocytes activation. On the other hand, the low dose of IGF-1 enhanced LPS-induced PMNs recruitment and blood-brain barrier (BBB) permeability, and caused intracerebral hemorrhage. At higher doses, co-application of IGF-1 with LPS resulted in a high mortality rate. Brains from the surviving rats showed massive PMN infiltration and intracerebral hemorrhage. However, these adverse effects were not found in rats treated with IGF-1 alone. This study provides the alarming evidence that in an acute inflammatory condition, IGF-1 may have severe, harmful effects on the developing brain.

A comparison of behavioural and histological outcomes of periventricular injection of ibotenic acid in neonatal rats at postnatal days 5 and 7.

Periventricular white matter injury (PVWMI) in premature babies is a major cause of cerebral palsy. Excitotoxic ibotenic acid (IBA) causes PVWMI-like lesions when injected into the white matter of neonatal rodents, however, whether it causes sensorimotor behavioural deficits that could also model cerebral palsy has not been tested. We compared IBA injection at postnatal day 7 (P7) when rodent development is equivalent to the stage of human corticospinal maturation vulnerable to PVWMI and P5 when rodent oligodendrocyte precursor cells are more vulnerable to excitotoxicity. IBA or saline were injected bilaterally into white matter between the external angle of the lateral ventricle and the forelimb sensorimotor cortex. By P14, IBA injection at P5 caused localised hypomyelination and cyst formation in this region, although cortical grey matter remained intact. Treatment at P7 produced less hypomyelination, but more widespread loss of neurofilament immunoreactivity. From P28 onwards, corticospinal function was assessed by testing reaching and retrieval of food rewards. All rats improved with age, but there was a consistent and significant difference between IBA treated rats (P5 and P7) and controls. Histological examination following testing revealed no difference in forebrain cross-sectional area but that the lateral ventricles were significantly larger in IBA treated animals than controls, especially at P7. P5 treatment caused a significantly reduced density of anti-myelin immunoreactivity in the corpus callosum compared to the anterior commissure that was not consistently seen following P7 treatment. We conclude that IBA induced lesions provide a satisfactory model of PVWMI, particularly when made at P5.

Metaanalysis of the effect of antenatal indomethacin on neonatal outcomes.

OBJECTIVE: The objective of the study was to determine whether indomethacin used as a tocolytic agent is associated with adverse neonatal outcomes. STUDY DESIGN: We used published guidelines of the Metaanalysis of Observational Studies in Epidemiology Group (MOOSE) to perform the metaanalysis. The search strategy used included computerized bibliographic searches of MEDLINE (1966-2005), PubMed (1966-2005), abstracts published in Obstetrics and Gynecology (1991-2005), abstracts published in Pediatric Research (1991-2005), and references of published manuscripts. Study inclusion criteria were publication in English, more than 30 deliveries less than 37 weeks' gestation, and meeting diagnostic criteria for individual neonatal outcomes. Exclusion criteria included case reports, case series, and multiple publications from the same author. Metaanalysis was performed using random effects model if there were more than 2 observational studies for a specific outcome. Eggers test was performed to exclude publication bias. Sensitivity analysis was performed to evaluate the effect of antenatal steroid exposure, gestation, and recent antenatal indomethacin exposure (duration of 48 hours or more between the last dose and delivery). RESULTS: Fifteen retrospective cohort studies and 6 case-controlled studies met inclusion criteria. Antenatal indomethacin was associated with an increased risk of periventricular leukomalacia (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.3-3.1). Recent exposure to antenatal indomethacin was associated with necrotizing enterocolitis (OR, 2.2; 95% CI; 1.1-4.2). Antenatal indomethacin was not associated with intraventricular hemorrhage, patent ductus arteriosus, respiratory distress syndrome, bronchopulmonary dysplasia, and mortality. CONCLUSION: Antenatal indomethacin may be associated with an increased risk of periventricular leukomalacia and necrotizing enterocolitis in premature infants and therefore should be used judiciously for tocolysis.

Periventricular leukomalacia and prenatal methamphetamine exposure: a case report.

Periventricular leukomalacia (PVL) is a complication of prematurity that carries a high risk of long-term neurologic morbidity. We report the first case, to our knowledge, of unexpected PVL associated with in utero methamphetamine exposure in a 30-week gestation premature infant with a benign hospital course, who subsequently developed cerebral palsy by 24 months of life.

No phenotype associated with established lipopolysaccharide model for cerebral palsy.

OBJECTIVE: Cerebral palsy (CP) is associated with childhood spasticity, seizures, and paralysis. Oligodendrocyte damage resulting in periventicular leukomalacia (PVL) in the developing brain has been implicated. Animal models of CP have used prenatal hypoxia and infection with histopathology of PVL as the end point. To evaluate whether this histologic end point is associated with a CP phenotype, we reproduced a lipopolysaccharide (LPS) model for PVL, 1 and evaluated developmental, behavioral, and motor outcomes. STUDY DESIGN: On gestational day 15, Fischer 344 rats were intracervically injected with .1 mg/kg LPS (n = 5) or saline (n = 4). After delivery, evaluation for developmental milestones was performed on days 1 to 21 (LPS = 45; control = 30 pups). Males were also tested at 2.5 months using open-field, rotarod, and anxiety tests. On day 21, 2 pups/litter were perfused for immunohistochemistry, and stained with 2 oligodendrocyte antibodies: 2', d'-cyclic nucleotide phosphodiesterase (CNP), and myelin proteolipid protein (PLP) with relative densities of staining assessed using NIH Image software. Statistical analysis included Mann-Whitney U and analysis of variance (ANOVA). RESULTS: LPS pups demonstrated decreased CNP (P = .04) and PLP (P = .06) staining, replicating the model. There was no difference seen in neonatal weight, righting, negative geotaxis, cliff aversion, rooting, forelimb grasp, audio startle, air righting, eye opening, and activity. Surprisingly, LPS-exposed neonatal rats mastered forelimb placement (P < .01) and surface righting (P = .02) earlier than control rats. There were no differences between adult groups in open field distance traveled (P = .8), open-field locomotion time (P = .6), rotarod (P = .6), or anxiety (P = .7). CONCLUSION: Histologic evidence of white matter damage can be replicated using an LPS model for intrauterine inflammation. Significant phenotypic differences consistent with the motor and cognitive damage sequelae of such lesions (ie, CP) were not demonstrated. When evaluating animal models, it is important to assess not only biochemical markers for human disease, but also clinically relevant phenotypes.

Possible antenatal and perinatal related factors in development of cystic periventricular leukomalacia.

Cystic periventricular leukomalacia (cPVL), the principal ischemic brain injury in premature infants, is characterized by necrosis of the white matter in the periventricular region and the major neuropathology for spastic motor deficits in cerebral palsy or epilepsy. Recent reports strongly suggest that the brain injury associated with cPVL may have already occurred in utero. In this study we searched retrospectively for possible clinical situations related to cPVL to facilitate assessment of optimal management. A total of 201 babies born at gestational ages from 24 to 33 weeks were entered into the study (1992-1997) and examined for involvement of 18 factors in cPVL retrospectively. And psychomotor development was examined at least until 18 months of corrected age. Among 201 premature babies 35 cases were diagnosed as cPVL later developed spastic diplegia. There are 23 cases of preeclampsia, no infant suffering from cPVL. In the univariate analysis, exposure to antenatal indomethacin, cord length > or =40 cm, and a low Apgar score were significantly associated with a 2-3 risk increased of cPVL occurrence, while antenatal magnesium sulfate reduced the risk. Chorioamnionitis was positively correlated with the risk, but did not reach statistical significance. In the multivariate analysis we found the statistical significance in exposure to antenatal indomethacin, a low Apgar score, and antenatal magnesium sulfate. Our results suggested that preeclampsia and antenatal exposure of magnesium sulfate reduced the risk while antenatal exposure of indomethacin and low Apgar score associated with the occurrence of cPVL. These findings support a growing consensus that cPVL is often the result of maternal and fetal factors as well as antenatal treatment.

N-acetylcysteine prevents endotoxin-induced degeneration of oligodendrocyte progenitors and hypomyelination in developing rat brain.

Periventricular leukomalacia (PVL), the dominant form of brain injury in premature infants, is characterized by diffuse white matter injury and is associated with cerebral palsy (CP). Maternal and placental infections are major causes of prematurity and identifiable etiology of PVL and CP. Here we have evaluated the therapeutic efficacy of N-acetylcysteine (NAC), a potent antioxidant and precursor of glutathione, to attenuate lipopolysaccharide (LPS)-induced white matter injury and hypomyelination in the developing rat brain, an animal model of PVL. Intraperitoneal pretreatment of pregnant female rats with NAC (50 mg/kg), 2 hr prior to administration of LPS at embryonic day 18 (E18), attenuated the LPS-induced expression of inflammatory cytokines such as tumor necrosis factor-alpha, interleukin-1beta, and inducible nitric oxide synthase in fetal rat brains. There were significantly reduced numbers of TUNEL(+) nuclei coimmunostained for platelet-derived growth factor-alphaR(+) [a surface marker for oligodendrocyte progenitor cells (OPCs)] at E20 in the subventricular zone of fetal rat brain in the NAC + LPS group compared with the untreated LPS group. Interestingly, immunostaining for O4 and O1 as markers for late OPCs and immature oligodendrocytes demonstrated fewer O4(+) and O1(+) cells in the LPS group compared with the NAC + LPS and control groups. Consistent with O4(+)/O1(+) cell counts, the expression of myelin proteins such as myelin basic protein, proteolipid protein, and 2'3'-cyclic nucleotide phosphodiesterase, including transcription factors such as MyT1 and Gtx, was less in the LPS group at late postnatal days, indicating severe hypomyelination in the developing rat brain when compared with NAC + LPS and control groups. Collectively, these data support the hypothesis that NAC may provide neuroprotection and attenuate the degeneration of OPCs against LPS evoked inflammatory response and white matter injury in developing rat brain. Moreover, these data suggest the possible use of NAC as a treatment for pregnant women with maternal or placental infection as a means of minimizing the risk of PVL and CP.

Intrauterine cerebral infarcts and bilateral frontal cortical leukomalacia following chronic maternal inhalation of carburetor cleaning fluid during pregnancy.

Little is known about the effect of inhalation of methanol and other solvents on the pregnancy and the growth of the fetus. We report a preterm male infant who developed cerebral infarcts in utero, leading to large areas of bilateral frontal cortical leukomalacia following chronic maternal inhalation of carburetor-cleaning fluid during pregnancy. The infant presented with acute fetal distress with significant metabolic acidosis at birth. Initial hypotonia was followed by generalized hypertonicity. This infant did not exhibit typical facial features of fetal alcohol syndrome.

The effect on motor cortical neuronal development of focal lesions to the sub-cortical white matter in the neonatal rat: a model for periventricular leukomalacia.

Periventricular leukomalacia (PVL) is either a diffuse or cystic lesion of the periventricular white matter that leaves the overlying cortical grey matter largely intact. It is believed to result from hypoxia occurring pre- or perinatally and is a major cause of cerebral palsy. We have modelled PVL in rats comparing the effects of discrete injections of 3-nitropropionic acid (3-NP), a mitochondrial toxin, ibotenic acid (IBA), a glutamate analogue, or saline into the sub-cortical white matter on postnatal day 7 (P7). Following recovery times ranging from 3 days to 4 weeks, forebrain sections were Nissl stained or immunostained for Bax, cJun, calbindin (CB), parvalbumin (PV) or non-phosphorylated neurofilaments (NPNF). Compared to saline injections, ibotenic acid caused large lesions of both grey and white matter not characteristic of periventricular leukomalacia. 3-Nitropropionic acid injections caused small focal lesions restricted to the sub-cortical white matter. 3-Nitropropionic acid treatment initially increased expression of the apoptosis promoting proteins Bax and cJun, as well as non-phosphorylated neurofilaments in cortical layer V overlying the injection site. Non-phosphorylated neurofilament expression distal to the lesion was decreased representing a loss of cortical axons, but persisted and even increased with time within the cortex, demonstrating persistence of the parent cell bodies and local sprouting of neurites. There were significantly fewer calbindin and parvalbumin positive neurones in the motor cortex (MC) side ipsilateral to the 3-nitropropionic acid injection compared to the contralateral side. These persistent differences in expression of activity sensitive calcium binding proteins suggest alterations in local cortical circuitry without substantial loss of grey matter as is characteristic of periventricular leukomalacia. Changes in expression of Bax, cJun and non-phosphorylated neurofilaments during normal development are also described.

[Influence of antenatal steroid therapy on newborn nervous system]. / Wplyw steroidoterapii prenatalnej na stan ukladu nerwowego noworodka.

OBJECTIVES: Analysis of the impact of prenatal glucocorticoids on the neurological outcome of a newborn. DESIGN: The authors reviewed the most current reports concerning the influence of antenatal steroid therapy (used to accelerate of fetal lung maturation) on neonates. In the study we discussed the influence of steroid therapy on growth and development of the brain, as well as the occurrence rate of the most common neurological abnormalities, such as: intraventricular haemorrhage and periventricular leukomalacia. MATERIALS AND METHODS: Recent literature review. RESULTS: We believe that use of antenatal corticosteroids remains a major factor in reducing neonatal mortality. Treatment with one course of betamethasone, as we know at the present time, is completely safe for a newborn's nervous system. Many courses of antenatal steroids may decrease fetal brain growth. Antenatal steroid therapy reduced the incidence of intraventricular haemorrhage in preterm infants. Use of betamethasone, but probably not dexamethasone, in antenatal therapy reduced the incidence of periventricular leukomalacia in extremely low weight infants. CONCLUSIONS: According to recent studies regarding probable unfavourable role of dexamethasone in neonatal neurological development we are of opinion that dexamethasone should be replaced by betamethasone in therapy of imminent preterm labour.

Association between the use of antenatal magnesium sulfate in preterm labor and adverse health outcomes in infants.

OBJECTIVE: The purpose of this study was to determine whether the use of antenatal magnesium sulfate prevents adverse outcomes (neonatal intraventricular hemorrhage, periventricular leucomalacia, death, and cerebral palsy). STUDY DESIGN: In a controlled trial, we randomized mothers in preterm labor to magnesium sulfate, "other" tocolytic, or placebo. At delivery, umbilical cord blood was collected for the later determination of serum ionized magnesium levels. Neonatal cranial ultrasound scans were obtained periodically for the diagnosis of intraventricular hemorrhage and periventricular leucomalacia. Among survivors, the diagnosis of cerebral palsy was made at age 18 months. RESULTS: Children with adverse outcomes had higher umbilical cord magnesium levels at delivery. In regression models that controlled for confounders, which included very low birth weight, magnesium remained a significant risk factor (adjusted odds ratio, 3.7; 95% CI, 1.1-11.9; P =.03). CONCLUSION: Contrary to original hypotheses, this randomized trial found that the use of antenatal magnesium sulfate was associated with worse, not better, perinatal outcome in a dose-response fashion.

Melatoninergic neuroprotection of the murine periventricular white matter against neonatal excitotoxic challenge.

Periventricular leukomalacia is one of the main causes of cerebral palsy. Perinatal white matter lesions associated with cerebral palsy appears to involve glutamate excitotoxicity and excess free radical production. When injected intracerebrally into newborn mice, the glutamatergic analog ibotenate induces white matter cysts mimicking human periventricular leukomalacia. Melatonin acts on specific receptors. It also exhibits intrinsic free radical scavenging properties. The goal of the present study is to determine whether melatonin can protect against excitotoxic lesions induced by ibotenate in newborn mice. Mice that received intraperitoneal melatonin had an 82% reduction in size of ibotenate-induced white matter cysts when compared with controls. Although melatonin did not prevent the initial appearance of white matter lesions, it did promote secondary lesion repair. Axonal markers supported the hypothesis that melatonin induced axonal regrowth or sprouting. The protective effects of melatonin were suppressed by coadministration of luzindole, a melatonin receptor antagonist. Forskolin, an adenylate cyclase activator, prevented the protective effects of melatonin; inhibitors of protein kinase C and mitogen-associated protein kinase had no detectable effect. Melatonin and derivatives that block cAMP production through activation of melatonin receptors could represent new avenues for treating human periventricular leukomalacia.