Circulating interferon-gamma and white matter brain damage in preterm infants

The fetal inflammatory response has been suggested as causal in neonatal morbidity. Serial levels of circulating cytokines were evaluated in 74 infants with a mean gestational age (GA) of 27.1 wk. Pro-inflammatory [tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), IL-1 beta, IL-2, IL-6, IL-8, IL-12] [corrected] and modulatory (IL-4, IL-10) cytokines were analyzed from cord blood, and at 6, 24 [corrected] and 72 h postnatal age. Measure of cytokine burden over time was assessed by calculating the area under curve (AUC) for analyzed levels (0-72 h). Premature rupture of membranes (PROM) was associated with higher levels of IL-2 at birth and at 6 h, of IFN-gamma at 6 and 24 h postnatal age and of TNF-alpha at 6 and 24 h. Levels of IFN-gamma at 6, 24, and 72 h were increased in infants developing white matter brain damage (WMD) compared with those without WMD. Infants with arterial hypotension requiring dopamine treatment had an increase in IL-6 with a peak at 6 h of age. Severe intraventricular hemorrhage (IVH) was associated with increase in AUC [(IL-6) and (IL-8), odds ratio (OR) 2.8 and 13.2 respectively], whereas white matter brain damage (WMD) [corrected] was associated with increase in AUC (IFN-gamma; OR, 26.0) [corrected] A fetal immune response with increased postnatal levels of IFN-gamma was associated with development of WMD. PROM was associated with a T-helper 1 cytokine response with increased levels of IFN-gamma. Type of inflammatory response appears of importance for subsequent morbidity.     

The relationship of CSF and plasma cytokine levels to cerebral white matter injury in the premature newborn

Ischemia and systemic infection are implicated in the etiology of periventricular white matter injury, a major cause of adverse motor and cognitive outcome in preterm infants. Cytokines are signaling proteins that can be produced as part of the inflammatory response to both ischemia and infection. The aim of this study was to relate cerebrospinal fluid (CSF) concentrations of IL-6, IL-8, IL-10, tumor necrosis factor alpha (TNF-alpha), and interferon gamma (IFN-gamma) to magnetic resonance-defined white matter injury in preterm infants. Relationships between CSF and plasma cytokine concentrations were also examined. Preterm infants (相似文献   

Elevation of cytokine concentrations in asphyxiated neonates

BACKGROUND: Various cytokines are reportedly associated with many neonatal diseases. Asphyxia is considered to result in ischemia-reperfusion injuries and induces abnormal inflammatory responses involving excessive cytokine production. OBJECTIVES: To evaluate alteration in sera levels of various cytokines/chemokines in case of perinatal asphyxia at birth. METHODS: In order to determine the concentrations of various cytokines/chemokines in sera, we used a highly sensitive fluorescence microsphere method. We measured the concentration of 8 types of cytokines/chemokines in sera obtained from 17 cases of asphyxia, 10 normal neonates, and 6 healthy adults. RESULTS: The concentrations of IL-6, IL-8, and IL-10 in the sera of asphyxiated neonates were higher than those in the normal neonates. Irrespective of the presence or absence of asphyxia, sera concentrations of IL-2, IL-4, IFN-gamma, and TNF-alpha were higher in the neonates than those in the adults. The concentration of IFN-gamma in the asphyxiated neonates was lower than that in the normal neonates. Sera levels of IL-10 were higher in the asphyxiated cases than those in the normal neonates. The sera levels of IL-6, IL-8, and IL-10 in asphyxiated neonates with either a poor outcome or death were higher than those without poor outcomes. CONCLUSIONS: The concentrations of various types of cytokines/chemokines were different in neonatal sera and some of them increased drastically during asphyxia. The concentration of an anti-inflammatory cytokine IL-10 was elevated in asphyxiated neonates immediately after birth, thereby suggesting that IL-10 might be associated with neuroprotective functions.     

Inflammatory markers in intrauterine and fetal blood and cerebrospinal fluid compartments are associated with adverse pulmonary and neurologic outcomes in preterm infants

Recent evidence strongly implicates the inflammatory response to intrauterine infection in the pathogenesis of neonatal brain and lung injury. We hypothesized that lung and brain injury in preterm infants occurs during a common developmental window of vulnerability as the result of an inflammatory response in different compartments. To determine whether inflammatory markers in these compartments are associated with bronchopulmonary dysplasia (BPD) or cranial ultrasound (CUS) abnormalities in infants <33 wk gestation age (GA) and <1501 g birth weight, we analyzed placental pathology and serum and cerebrospinal fluid (CSF) IL-6, IL-1beta, and tumor necrosis factor-alpha (TNF-alpha) concentrations in 276 infants. Logistic regressions were performed stratified by GA. Histologic chorioamnionitis was significantly associated with BPD in infants /=17 pg/mL was associated with an abnormal CUS in infants >28 wk GA (OR 3.36, p = 0.023) but not /=6.5 pg/mL and TNF-alpha >/=3 pg/mL were associated with abnormal CUS in infants /=28 wk GA. These data suggest that in infants 相似文献   

宫内大肠杆菌感染导致新生大鼠脑白质损伤的实验研究

目的　探讨宫内感染后胶质纤维酸性蛋白 (GFAP)、GFAPmRNA和白介素 1βmRNA(IL 1βmRNA)、肿瘤坏死因子 αmRNA(TNF αmRNA)在新生大鼠脑组织中的变化。 方法　建立宫内大肠杆菌感染的大鼠模型 ,应用HE染色和免疫组化方法研究新生 1、3、7日龄大鼠脑白质组织病理特点和GFAP表达变化以及RT PCR法检测GFAPmRNA、IL 1βmRNA和TNF αmRNA的表达变化。结果　宫内感染后 7日龄大鼠脑白质病理改变包括脑白质染色淡 ,结构疏松等。感染组 7日龄大鼠GFAP阳性细胞数在脑室旁白质和海马区明显多于对照组 (脑室旁白质 9 73± 3 5 5vs 5 6 7± 1 90 ,P <0 0 5 ;海马 7 81± 3 6 1vs 2 16± 1 11,P <0 0 5 ) ;在胼胝体区两组比较差异无显著意义(P >0 0 5 )。感染组 1、3日龄大鼠GFAPmRNA表达水平明显高于对照组 (1日龄 0 2 5± 0 0 7vs0 15± 0 0 8,P <0 0 5 ;3日龄 0 5 0± 0 0 9vs 0 39± 0 0 8,P <0 0 5 ) ;而 7日龄大鼠GFAPmRNA表达水平两组比较差异无显著意义 (P >0 0 5 )。感染组 1日龄大鼠IL 1βmRNA和TNF αmRNA表达水平均明显高于对照组 (IL 1βmRNA :0 83± 0 19vs 0 5 0± 0 30 ,P <0 0 5 ;TNF αmRNA :0 74±0 30vs 0 30± 0 2 0 ,P <0 0 5 )。 3、7日龄大鼠IL 1βmRNA和TNF      

Cerebral white matter damage in the preterm infant: pathophysiology and risk factors

Based on clinical, epidemiologic, and experimental studies, the aetiology of white matter damage, specifically periventricular leukomalacia (PVL), is multifactorial and involves pre- and perinatal factors possibly including genetic factors, hypoxic-ischaemic insults, infection, excess cytokines, free radical production, increased excitatory amino acid release, and trophic factor deficiencies. The article summarizes research findings about the aetiology of white matter damage and cerebral palsy in preterm infants. The information is organized according to specific antecedents, for which we present epidemiological and neurobiological data. The most important prenatal factor appears to be intrauterine infection. We discuss the evidence supporting the hypothesis that the foetal inflammatory response contributes to neonatal brain injury and later developmental disability. We recently established an animal model of excitotoxic lesions in the developing mouse brain. Brain damage was induced by intra-cortical injections of ibotenate, a glutamatergic agonist. When administered on post-natal day 5 ibotenate induced the formation of white matter cysts. Our animal model could be used to further explore the mechanisms involved in the formation of PVL. Potentially preventive strategies will be discussed.     

Interleukin-6 and interleukin-8 are elevated in the cerebrospinal fluid of infants exposed to chorioamnionitis

BACKGROUND: The clinical or histologic diagnosis of chorioamnionitis has been associated with an increased risk of neuropathology and adverse neurologic outcomes in premature and term infants. Inflammatory cytokines have been implicated in the pathogenesis of these processes. The objective of this study was to determine whether exposure to chorioamnionitis and fetal inflammatory syndrome is associated with elevated concentrations of inflammatory cytokines (TNF-alpha, IL-6, and IL-8) in the CSF of term and preterm infants. METHODS: Eighty-four mother/infant pairs were studied, 54 infants were premature. Twenty-eight showed signs of maternal (n = 14), or fetal (n = 14) inflammation based on placental pathology; mothers of 24 infants showed signs of clinical chorioamnionitis not confirmed by placental pathology and 32 infants were considered as 'controls' since they had only transient difficulty adjusting to extra-uterine life warranting evaluation for sepsis. The cytokine concentrations in the CSF were measured within 24 h of birth. RESULTS: When compared to the control group (IL-8 = 341 +/- 170 pg/ml and IL-6 = 7.4 +/- 1.8 pg/ml) significantly higher concentrations of IL-8 were detected in the CSF of infants exposed to clinical chorioamnionitis (1,854 +/- 878 pg/ml; p = 0.001) and maternal/fetal inflammation (1,754 +/- 787 pg/ml; p = 0.001) and of IL-6 in infants with maternal/fetal inflammation (47.6 +/- 45.1 pg/ml; p = 0.01). CONCLUSIONS: These results indicate that infants exposed to clinical chorioamnionitis, or inflammation in utero, experience at least a transient elevation in inflammatory cytokines in CSF.     

Melatonin reduces inflammation and cell death in white matter in the mid-gestation fetal sheep following umbilical cord occlusion

The premature infant is at increased risk of cerebral white matter injury. Melatonin is neuroprotective in adult models of focal cerebral ischemia and attenuates ibotenate-induced white matter cysts in neonatal mice. Clinically, melatonin has been used to treat sleep disorders in children without major side effects. The aim of this study was to investigate the protective and anti-inflammatory effects of melatonin in the immature brain following intrauterine asphyxia. Fetal sheep at 90 d of gestation were subjected to umbilical cord occlusion. Melatonin (20 mg/kg, n = 9) or vehicle (n = 10) was administered IV to the fetus, starting 10 min after the start of reperfusion and continued for 6 h. Melatonin treatment resulted in a slower recovery of fetal blood pressure following umbilical cord occlusion, but without changes in fetal heart rate, acid base status or mortality. The production of 8-isoprostanes following umbilical cord occlusion was attenuated and there was a reduction in the number of activated microglia cells and TUNEL-positive cells in melatonin treated fetuses, suggesting a protective effect of melatonin. In conclusion, this study shows that melatonin attenuates cell death in the fetal brain in association with a reduced inflammatory response in the blood and the brain following intrauterine asphyxia in mid-gestation fetal sheep.     

Maternal endotoxin-induced preterm birth in mice: fetal responses in toll-like receptors, collectins, and cytokines

Major cause of prematurity is spontaneous preterm birth (PTB) associated with intrauterine inflammation. Our aim was to establish a model of endotoxin Lipopolysaccharide-induced PTB of live-born pups and to study early immune activation in fetal and maternal compartments. Expression of several proteins that bind microbes (Toll-like receptors TLR4, TLR2; surfactant proteins SP-A, SP-D) was analyzed. At 16 or 17 d of gestation, C57BL/6 dams received a single dose of intraperitoneal LPS, leading to PTB within 17 h. Cytokine levels increased in maternal serum, followed by a modest increase in fetal serum and in amniotic fluid. In uterus, placenta, and fetal membranes, LPS mostly increased the expressions of TLR, SPs, and cytokines. The number of TLR2-positive macrophages increased in labyrinthine placenta. In fetal lung, intestine, liver, and brain there were modest changes in cytokine expressions. In fetal lung, SP and TLR mRNAs decreased and TLR2-positive macrophages redistributed around vessels. LPS-induced fetal deaths associated with early age (16 d gestation) rather than with proinflammatory activation. Here we propose that maternal LPS response leads to PTB and acute decrease of immune proteins in epithelial lining of fetal lung. Instead, acceleration of lung maturity has been previously observed in intraamniotic inflammation.     

Cytokines in the placenta of Pakistani newborns with and without intrauterine growth retardation

Although intrauterine growth retardation (IUGR) is a major risk factor for increased neonatal mortality and morbidity, the mechanisms behind it are not clear. We analyzed cytokine gene expression and gene polymorphisms in infants with and without IUGR in Pakistan, where IUGR is very common. 45 IUGR and 55 control mother/infant pairs were studied. mRNA for IL-10, IL-8, TNF-alpha, TGF-beta, IL-6, IL-4, IL-1beta, IL-12, IFN-gamma and GAPDH was quantified with RT-PCR from placenta. Cytokine and cytokine receptor gene polymorphisms for -1087IL10, -308TNFA, -174IL6, +915TGFB1, intron 2 IL1RN, +36TNFR1, 150V IL4RA and -159CD14 were determined from genomic DNA. The serum levels of IL-1beta, IL-6, IL-8, IL-10, IL-12, TNF-alpha and TGF-beta were measured. There was a significant decrease of IL-10 and IL-12, but increase of TGF-beta in the decidua and similarly decrease of IL-10, but increase of TGF-beta in the trophoblasts of the IUGR placentas compared with the non-IUGR placentas. We found significantly lower levels of IL-1beta in serum from the mothers of the IUGR infants and of TGF-beta in serum of the infants with IUGR compared with the non-IUGR infants. We note that the IL-10 mRNA expression in the decidua was down-regulated, but the TGF-beta mRNA up-regulated in IUGR placentas of mothers from a population with multiple risk factors for IUGR. We propose that the low IL-10 in the placenta may be involved in the pathogenesis of IUGR and might possibly be treatable.     

Attenuation of lipopolysaccharide-induced inflammatory response and phospholipids metabolism at the feto-maternal interface by N-acetyl cysteine

Maternal microbial infections cause adverse fetal developmental outcomes including embryonic resorption, intrauterine fetal death, and preterm labor. Recent studies demonstrated that oxidative-stress plays an important role in chorioamniotitis pathogenesis. Herein we investigated the effect of N-acetyl cysteine (NAC) on lipopolysaccharide (LPS)-induced preterm labor and fetal demise in murine model. Lipopolysaccharide exposure at embryonic day 18 demonstrated an increase in the abortion rate and fetal demise in pregnant rats. This was associated with increase in an inflammatory response (cytokines, chemokines, and iNOS expression) and infiltration of leukocytes (monocytes and polymorphonuclear cells) in the placenta. There was increased expression of cytosolic and secretary phospholipase A2 with increased secretion of prostaglandin-2 and leukotriene B4 in the placenta, suggestive of increased metabolism of phospholipids. In addition, expression of cycloxygenase-2 and malondialdehyde production (oxidative-stress marker) was increased in the placenta. Conversely, NAC pretreatment abolished these effects of LPS in the placenta. Collectively, these data provide evidence that LPS-induced increased inflammation and metabolism of phospholipids at the feto-maternal interface (placenta) is critical for preterm labor and fetal demise during maternal microbial infections which could be blocked by antioxidant-based therapies.     

内毒素致胎鼠脑白质损伤后Bcl-2和Bax蛋白表达的研究

目的 探讨内毒素致胎鼠脑白质损伤后凋亡蛋白Bcl-2、Bax的表达及其意义.方法 孕鼠随机分为两组:感染组和对照组.感染组:建立宫内感染的动物模型,孕鼠怀孕15 d腹腔注射内毒素;对照组:孕鼠怀孕15 d腹腔注射生理盐水.分别于给药后2、4、12、24、72 h剖腹取胎鼠,取脑组织行组织病理学检查,观察胎盘及胎鼠脑组织病理特点,用免疫组织化学方法检测胎鼠脑组织凋亡蛋白Bcl-2、Bax的表达.结果 感染组胎盘组织见中性粒细胞浸润,胎鼠脑组织病理改变包括脑白质染色减淡,结构疏松等.感染组胎鼠脑组织凋亡蛋白Bcl-2的表达自2 h开始逐渐下降,而Bax的表达自2 h逐渐升高,均于12h达到峰值.2h感染组Bcl-2、Bax的阳性细胞百分数与对照组相比,差异无显著性(P>0.05);而4 h、12 h、24 h和72 h感染组与对照组相比,差异有非常显著性(P<0.01).感染组Bax与Bcl-2的比值均明显高于对照组,在各观察时间点两组相比,差异有非常显著性(P<0.01).结论 内毒素诱导是制备胎鼠脑白质损伤的一种有效形式.在胎鼠脑白质损伤中Bcl-2可能抑制细胞凋亡,Bax可能诱发细胞凋亡,两者的比率变化可能对脑白质损伤后细胞凋亡的调节起重要作用.     

Postnatal development of monocyte cytokine responses to bacterial lipopolysaccharide

Early childhood is a period of heightened susceptibility to infection due to immaturity of the immune system, and the nature of these developmental deficiencies is only partially understood. In this study, we focused on the ontogeny of the innate immune system by investigating the capacity of mononuclear cells to secrete a wide spectrum of inflammatory cytokines in response to interferon (IFN)-gamma priming and lipopolysaccharide (LPS) stimulation, namely IL-6, IL-10, IL-12, IL-18, IL-23, tumor necrosis factor (TNF)-alpha, and myxovirus resistance protein A, induced by type-I IFN, at several time points between birth (cord blood) and adulthood. Competence to produce all these cytokines followed a similar developmental pattern, with slow postnatal up-regulation from the response observed in cord blood. Unexpectedly, IL-6, IL-10, TNF-alpha, and IFN-gamma showed slow postnatal up-regulation but also elevated cord blood responses equal to or greater than the adult level. This was transient and not observed at 2 mo of age, and was not related to predelivery stress of the newborns. Variations in Toll-like receptor (TLR)4 function may account for these age related differences in cytokine responses, as TLR4 expression on neonatal monocytes post LPS stimulation was elevated and sustained relative to infants and adults.     

Rupture très prématurée des membranes: physiopathologie des conséquences neurologiques

The premature rupture of membranes (PROM) is responsible for 30 % of the premature births because of a high risk of associated chorioamnionitis. PROM and the perinatal infection are recognized as 2 of the main risk factors of periventricular leukomalacia and white matter disease in very preterm neonates. Inflammation associated with PROM is likely to induce neuronal or glial cell death at a developmental stage of great vulnerability for the developing brain. Several mechanisms (release of cytokines, accumulation of free radicals, excitotoxicity, apoptosis...) account for this deleterious effect.The decision to actively extract a fetus subjected to a fetal inflammatory response syndrome should take account of the risks of a proved intrauterine infection for both the mother and the fetus and the risks for the neonate related to a very preterm birth per se. A reasonable attitude seems not to maintain a fetus in an undoubtful septic context in utero if a preterm birth in the very short term appears unevitable. Practically, no consensus gives a recommendation between aggressive or conservative management in case of PROM within 30 and 34 weeks'gestation. Expectant management seems to be indicated before 28 weeks'gestation and intentional delivery could be recommended beyond 34 weeks'gestation due to increased maternal risks compared to relatively low incidence of the complications of prematurity at this term.     

Cerebral inflammatory response after fetal asphyxia and hyperoxic resuscitation in newborn sheep

Resuscitation with pure oxygen at birth after fetal asphyxia may aggravate brain damage by inducing pro-inflammation. The toll-like receptors (TLRs) may serve a pro-inflammatory role in hyperoxemia during ischemia-reperfusion. Sixteen near-term fetal sheep (132-136 d) were subjected to 10 min of cord occlusion, delivery and mechanical ventilation with 100% O2 (n = 8), or 21% O2 (n = 8) for 30 min followed by normoxemia for 90 min. Eight sheep fetuses were delivered immediately with inspired O2 targeted at normoxemia for 120 min (controls). Levels and distributions of mRNAs for IL-1beta, TNF-alpha, IL-12p40, IL-18, IL-6, IL-10, IFN-gamma, TLR-2, -3 and -4 in cerebral tissue at 2 h after birth were evaluated with real-time polymerase chain reaction (PCR) and in situ hybridization. Expressions of IL-1beta, IL-12p40, TLR-2, and TLR-4 were increased in cortex/subcortex after resuscitation with 100% O2 compared with 21% O2 (all p < 0.05) and to controls (all p < 0.05). Increased cellular expression of IL-1beta was localized to sub-meningeal cortical layers and to sub-cortical white matter. Hyperoxic resuscitation at birth following fetal asphyxia induces a cerebral pro-inflammatory response with an up-regulation of TLR-2 and -4. These may be early events leading to increased tissue damage after exposure to hyperoxemia at birth.     

Lipopolysaccharide-induced inflammation and perinatal brain injury

Both energy failure and infections are important risk factors for brain injury in term and preterm infants. In this review we focus on recent experimental studies that have examined the effects of lipopolysaccharide (LPS) exposure to the fetus or neonate and the interaction of LPS with other events. Intracerebral LPS injections induce a marked cerebral cytokine response and prominent white matter lesions. LPS administered intravenously to the fetus also induces gross lesions, which are mainly localised to the white matter and are accompanied by activation of inflammatory cells. Cerebral effects following fetal LPS exposure via more distant routes, such as intracervical, intrauterine or maternal LPS administration, are characterised by reductions in oligodendrocyte or myelin markers without macroscopic lesions being evident. Both antenatal and neonatal LPS exposures increase the sensitivity of the brain to subsequent hypoxic/ischaemic events, even in adulthood. These studies suggest that fetal inflammation is the strongest predictor of brain lesions.     

Development of neonatal murine microglia in vitro: changes in response to lipopolysaccharide and ischemia-like injury

Hypoxic/ischemic brain injury in the neonate can activate an inflammatory cascade, which potentiates cellular injury. The role of microglia in this inflammatory response has not been studied extensively. We used an in vitro model of murine microglia to investigate changes in microglial cytokine release and injury during early development. Isolated microglia were subjected to lipopolysaccharide (LPS) activation or injury by glucose deprivation (GD), serum deprivation (SD), or combined oxygen-glucose deprivation (OGD) for varying durations. The extent and the type of cell death were determined by trypan blue, terminal deoxynucleotidyl end-nick labeling, and annexin staining. Early-culture microglia (2-3 d in purified culture) showed significantly more apoptotic cell death after SD, GD, and OGD compared with microglia maintained in culture for 14-17 d. Measurements of tumor necrosis factor-alpha (TNF-alpha) and IL-1beta in culture media demonstrated that OGD induced greater release of both TNF-alpha and IL-1beta than LPS activation, with early-culture microglia producing more TNF-alpha compared with late-culture microglia. Microglia that are cultured for a short time are more sensitive to ischemia-like injury in vitro than those that are cultured for longer durations and may contribute to worsening brain injury by increased release of inflammatory cytokines. Inhibition of microglial activation and decreasing proinflammatory cytokine release may be targets for reduction of neonatal hypoxic/ischemic brain injury.     

Elucidating the early signal transduction pathways leading to fetal brain injury in preterm birth

Adverse neurologic outcome, including cerebral palsy, is a significant contributor to long-term morbidity in preterm neonates. However, the mechanisms leading to brain injury in the setting of a preterm birth are poorly understood. In the last decade, there has been a growing body of evidence correlating infection or inflammation with preterm birth. The presence of intrauterine inflammation significantly increases the risk for adverse neurologic outcome in the neonate. These studies were performed to elucidate the early signal transduction pathways activated in the fetal brain that may result in long-term neurologic injury. Using our mouse model of localized intrauterine inflammation, the activation of TH1/TH2 pathways in the placenta, fetus corpus, fetal liver, and fetal brain was investigated. Additional studies determined whether activation of TH1/TH2 pathways could promote cell death and alter glial development. Real-time PCR studies demonstrated that a robust TH1/TH2 response occurs rapidly in the fetal brain after exposure to intrauterine inflammation. The cytokine response in the fetus and placenta was not significantly correlated with the response in the fetal brain. Along with an immune response, cell death pathways were activated early in the fetal brain in response to intrauterine LPS. Implicating TH1/TH2 and cell death pathways in permanent brain injury are our findings of an increase in GFAP mRNA and protein as well as a loss of pro-oligodendrocytes. With increased understanding of the mechanisms by which inflammation promotes brain injury in the preterm neonate, identification of potential targets to limit adverse neonatal outcomes becomes possible.     

Feeding a formula supplemented with long chain polyunsaturated fatty acids modifies the "ex vivo" cytokine responses to food proteins in infants at low risk for allergy

Long chain polyunsaturates (LCP) status during the early neonatal period is associated with a reduced risk of atopic symptoms and later allergies. In this study, we characterized the immune response of low-risk, term, formula-fed infants randomized at 相似文献