Population cohort associating chorioamnionitis, cord inflammatory cytokines and neurologic outcome in very preterm, extremely low birth weight infants

Interleukin-6 -174 and -572 genotypes and the volume of deep gray matter in preterm infants

Preterm infants have smaller cerebral and cerebellar volumes at term compared with term born infants. Perinatal factors leading to the reduction in volumes are not well known. IL-6 -174 and -572 genotypes partly regulate individual immunologic responses and have also been connected with deviant neurologic development in preterm infants. Our hypothesis was that IL-6 -174 and -572 genetic polymorphisms are associated with brain lesions and regional brain volumes in very low birth weight or in very preterm infants. DNA was genotyped for IL-6 -174 and -572 polymorphisms (GG/GC/CC). Study infants (n = 175) were categorized into three groups according to the most pathologic brain finding in ultrasound examinations until term. The brain MRI performed at term was analyzed for regional brain volumes. Analyzed IL-6 genotypes did not show statistically significant association with structural brain lesions. However, IL-6 -174 CC and -572 GG genotypes associated with reduced volume of one brain region, the combined volume of basal ganglia and thalami, both in univariate and in multivariate analyses (p = 0.009, 0.009, respectively). The association of IL-6 -174 and -572 genetic polymorphisms with smaller volumes in deep gray matter provides us new ways to understand the processes leading to neurologic impairments in preterm infants.

Cord immunoproteins as predictors of respiratory outcome in preterm infants

OBJECTIVE

The purpose of this study was to evaluate the role of cord blood proteins and antenatal factors in the prediction of respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD).

STUDY DESIGN

The prospectively collected cohort included 163 infants. All infants were born between 1998-2002 in a single regional hospital before 32 weeks of gestation and survived the first hospitalization. Altogether, 107 cord blood proteins were analyzed. Twenty-two antenatal clinical factors were included in the data mining and logistic regression analyses.

RESULTS

The incidence of RDS was 64% and of BPD was 25%. Histologic chorioamnionitis protected from RDS (odds ratio [OR], 0.24; 95% confidence interval [CI], 0.11-0.53; P < .001). Besides the length of gestation, other clinical factors poorly predicted the outcomes. Matrix metalloproteinase-9 independently predicted RDS (OR, 8.3; 95% CI, 3.0-23.1; P < .001). Soluble glycoprotein 130 independently predicted BPD (OR, 6.07; 95%CI, 2.20-16.7; P < .001).

CONCLUSION

Specific antenatal immunologic activation predicts either acute or chronic respiratory disease in very preterm infants.

Blood cytokines during the perinatal period in very preterm infants: relationship of inflammatory response and bronchopulmonary dysplasia

OBJECTIVE

To evaluate the influence of chorioamnionitis (CA) on plasma cytokines and the cytokine-associated risk of bronchopulmonary dysplasia (BPD) during the perinatal period.

STUDY DESIGN

Eleven cytokines from 128 very low gestational age infants were analyzed from cord blood and from plasma at ages 1 day and 7 days after birth. The diagnosis of CA was based on histology of the placenta, fetal membranes, and umbilical cord. Neonatal risk factors were recorded.

RESULTS

In the 48 infants born with CA, high concentrations of inflammatory cytokines in cord blood decreased during the first postnatal day. Inflammatory cytokines in cord blood was associated with the severity of CA. At 1 day after birth, the concentration of interleukin (IL)-8 predicted the risk of BPD. For the 75 infants born without CA, cytokine concentrations increased after birth. For the 128 infants born with or without CA, at 1 day after birth, the concentrations of IL-8, granulocyte colony-stimulating factor, and anti-inflammatory IL-10 were associated with the risk of BPD, after adjustment for the duration of gestation and severity of respiratory distress during the first day.

CONCLUSIONS

In infants exposed to CA, insufficient inhibition of high fetal inflammatory cytokine response shortly after birth may increase the risk of BPD.

Cytokines and perinatal brain damage

Perinatal brain damage has been implicated in the pathogenesis of neurodevelopmental impairments and psychiatric illnesses. This article reviews evidence that infection outside of the brain can damage the brain, and discusses specific cytokines and pathomechanisms that probably mediate the putative effect of remote infection on the developing brain. Events associated with increased circulating inflammatory cytokines, chemokines, and immune cells are described. Finally, studies of genetic variation in susceptibility to cytokine-related brain damage are reviewed.

Higher cord blood levels of mannose-binding lectin-associated serine protease-2 in infants with necrotising enterocolitis

Necrotising enterocolitis (NEC) causes significant morbidity and mortality in premature infants. The role of innate immunity in the pathogenesis of NEC remains unclear. Mannose-binding lectin (MBL) recognizes microorganisms and activates the complement system via MBL-associated serine protease-2 (MASP-2). The aim of this study was to investigate whether MBL and MASP-2 are associated with NEC. This observational case-control study included 32 infants with radiologically confirmed NEC and 64 controls. MBL and MASP-2 were measured in cord blood using ELISA. Multivariate logistic regression was performed. Of the 32 NEC cases (median gestational age, 30.5 wk), 13 (41%) were operated and 5 (16%) died. MASP-2 cord blood concentration ranged from undetectable (<10 ng/mL) to 277 ng/mL. Eighteen of 32 (56%) NEC cases had higher MASP-2 levels (> or =30 ng/mL) compared with 22 of 64 (34%) controls (univariate OR 2.46; 95% CI 1.03-5.85; p = 0.043). Higher cord blood MASP-2 levels were significantly associated with an increased risk of NEC in multivariate analysis (OR 3.00; 95% CI 1.17-7.93; p = 0.027). MBL levels were not associated with NEC (p = 0.64). In conclusion, infants later developing NEC had significantly higher MASP-2 cord blood levels compared with controls. Higher MASP-2 may favor complement-mediated inflammation and could thereby predispose to NEC.

Histological inflammatory responses in the placenta and early neonatal brain injury

We investigated the relationship between the severity of histological inflammatory responses in the placenta, chorionic plate, and umbilical cord in conjunction with the intraventricular hemorrhage (IVH) risk in premature infants. Clinical data were prospectively collected for 287 consecutive premature neonates born before 32 completed weeks of gestation and admitted to the level III neonatal intensive care unit of the Department of Pediatrics at Padua University from January 1999 to December 2004. Placental histology for histological chorioamnionitis (HCA) was graded and scored according to Redline and others. The diagnosis of IVH (grades I-IV) was graded according to Volpe's classification. Among the placentas of the 287 preterm examined infants, 68 (23.6%) were diagnosed with acute HCA. Overall incidence of IVH was 11.8%. Of 68 preterm neonates with HCA, 11 developed IVH (16.1%). Maternal HCA at the higher grades and stages increased the risk of IVH: 7 (64%) of the 11 preterm infants with maternal HCA grade 3 developed IVH (RR; 95% CI 2.05; 1.1-3.6) and 8 (73%) of the 11 preterm neonates with stage 3 developed IVH (RR; 95% CI 1.59; 1.0-2.5). Conversely, fetal inflammation was not associated with an increased risk of IVH. In conclusion, the IVH risk in preterm infants at less than 32 gestation weeks is significantly associated with severe grade and stage maternal HCA inflammatory scores.

Inflammation at birth is associated with subnormal development in very preterm infants

Preterm birth carries a risk for impaired developmental outcome. We have previously described an association between increased levels of proinflammatory cytokines during the first 72 postnatal hours and cerebral damage as detected by ultrasound in a cohort of 74 very preterm infants. Sixty-seven of 71 surviving children with a mean gestational age of 27.1 (2.0) wk were examined at 2 y corrected age with a standardized neurologic examination and with Bayley Scales of Infant Development. We hypothesized that proinflammatory cytokine concentrations at or shortly after birth would be associated with an adverse developmental outcome. Increased concentrations of TNF-alpha in cord blood odds ratio (95% confidence interval) 3.3 (1.1-10.2), p = 0.013 and at 6 h 7.8 (0.9-71.8), p = 0.015 and of IL-6 in cord blood 1.7 (1.0-2.9), p = 0.048 were associated with psychomotor developmental index <85. Increased concentrations of TNF-alpha in cord blood odds ratio (95% confidence interval) 3.6 (1.002-12.8), p = 0.044 and of IL-8 in cord blood 3.5 (1.2-10.6), p = 0.023 were associated with cerebral palsy. Associations of TNF-alpha and IL-8 in cord blood with the respective outcome measures remained significant after adjustment for other clinical variables. Proinflammation at birth is associated with impaired functional outcome at 2 y of corrected age in children with very preterm birth.

Interleukin-6 polymorphism is associated with chorioamnionitis and neonatal infections in preterm infants

OBJECTIVES

To evaluate whether genotypes of interleukin (IL)-6 gene promoter positions -174 and -572 are associated with histologic chorioamnionitis and neonatal inflammatory disease in preterm infants.

STUDY DESIGN

DNA from very low birth weight or very preterm infants (n = 107) was genotyped for IL-6-174 and -572 polymorphisms (GG/GC/CC). The placentas were analyzed for histological inflammatory findings. Data on neonatal inflammatory diseases, including chronic lung disease (CLD), necrotizing enterocolitis (NEC), and septicemia, were collected using the definitions of the Vermont Oxford Network database.

RESULTS

In univariate analyses, the IL-6-174 GG genotype was associated with a higher incidence of histologic chorioamnionitis. In multivariate analyses, the -174 GG and -572 GC genotypes were correlated with histologic chorioamnionitis (P = .039 and .009, respectively). Gestational age was not associated with genotype polymorphisms. IL-6-174 genotypes were not associated with CLD and/or NEC, but the CC genotype was correlated with septicemia in both univariate and multivariate analyses (P = .027). IL-6-572 genotypes were not associated with neonatal inflammatory disease.

CONCLUSIONS

The IL-6-174 GG and -572 GC genotypes were associated with a higher incidence of histologic chorioamnionitis, and the IL-6-174 CC genotype was associated with septicemia in preterm infants. These findings suggest that the genetic composition of the IL-6 promoter area plays a significant role in the pathogenesis of chorioamnionitis and neonatal infections.

Is cerebral palsy preventable?

PURPOSE OF REVIEW

To use evidence of good medical quality to update information on strategies for prevention of cerebral palsy, and on the success of these preventive efforts to date.

RECENT FINDINGS

Causes of cerebral palsy, and therefore promising approaches to prevention, differ by gestational age group and by clinical subtype. Neuroimaging and neuropathology indicate the importance of white matter disorders and of ischemic stroke in cerebral palsy; birth asphyxia, congenital malformations, placental pathology, and genetic variants also contribute to cerebral palsy risk. Multiplicity of risk factors markedly increases risk. Recent studies indicate that mild hypothermia lessens cerebral palsy risk in term infants with moderate neonatal encephalopathy, and the possibility that administration of magnesium sulphate to women in preterm labor may aid in primary prevention of cerebral palsy in very preterm infants.

SUMMARY

Past efforts to prevent cerebral palsy have not had the benefits sought, but recent results provide new hope and new challenges.

Pathogenesis of cerebral white matter injury of prematurity

Cerebral white matter injury, characterised by loss of premyelinating oligodendrocytes (pre-OLs), is the most common form of injury to the preterm brain and is associated with a high risk of neurodevelopmental impairment. The unique cerebrovascular anatomy and physiology of the premature baby underlies the exquisite sensitivity of white matter to the abnormal milieu of preterm extrauterine life, in particular ischaemia and inflammation. These two upstream mechanisms can coexist and amplify their effects, leading to activation of two principal downstream mechanisms: excitotoxicity and free radical attack. Upstream mechanisms trigger generation of reactive oxygen and nitrogen species. The pre-OL is intrinsically vulnerable to free radical attack due to immaturity of antioxidant enzyme systems and iron accumulation. Ischaemia and inflammation trigger glutamate receptor-mediated injury leading to maturation-dependent cell death and loss of cellular processes. This review looks at recent evidence for pathogenetic mechanisms in white matter injury with emphasis on targets for prevention and treatment of injury.

Inflammation in pregnancy: its roles in reproductive physiology, obstetrical complications, and fetal injury

Fetal development and growth occur in a sterile amniotic cavity while first exposure to microorganisms happens at birth. However, at least 25% of all preterm births, the leading cause of perinatal morbidity and mortality worldwide, occur in mothers with microbial invasion of the amniotic cavity. Microbial attack of the fetus takes place in approximately 10% of pregnancies with intra-amniotic infection, and the human fetus is capable of deploying an inflammatory response (cellular and humoral) in the mid-trimester of pregnancy. The onset of premature labor in the context of infection is mediated by pro-inflammatory cytokines, such as interleukin (IL)-1beta and tumor necrosis factor alpha (TNF-alpha), as these cytokines are produced by intrauterine tissues in response to microbial products, can stimulate prostaglandin production, and induce labor in animals. Moreover, knockout experiments suggest that infection is less likely to lead to premature labor when the IL-1 and TNF signaling pathways are disrupted. A fetal inflammatory systemic response occurs in a fraction of fetuses exposed to microorganisms in utero, and is associated with the impending onset of labor as well as multisystem organ involvement. Neonates born with funisitis, the histologic marker of such inflammation, are at increased risk for neurologic handicap and cerebral palsy. Evidence has begun to accumulate that gene-environment interactions determine the likelihood of preterm labor and delivery and, probably, the risk of fetal injury. Fetal inflammation has emerged as a major mechanism of disease responsible for complications in the perinatal period (in utero and in the first 28 days of life), as well as in infancy. Moreover, reprogramming of the fetal immune response may predispose to diseases in adulthood.

The fetal inflammatory response syndrome

The fetal inflammatory response syndrome (FIRS) is a condition characterized by systemic inflammation and an elevation of fetal plasma interleukin-6. This syndrome has been observed in fetuses with preterm labor with intact membranes, preterm prelabor rupture of the membranes, and also fetal viral infections such as cytomegalovirus. FIRS is a risk factor for short-term perinatal morbidity and mortality after adjustment for gestational age at delivery and also for the development of long-term sequelae such as bronchopulmonary dysplasia and brain injury. Multiorgan involvement in FIRS has been demonstrated in the hematopoietic system, thymus, adrenal glands, skin, kidneys, heart, lung, and brain. This article reviews the fetal systemic inflammatory response as a mechanism of disease. Potential interventions to control an exaggerated inflammatory response in utero are also described.

Assessment of serum interleukin-6 with a rapid test. The diagnosis of neonatal sepsis can be established or ruled out

Bevezetés: A neonatális szepszis mortalitása magas, és koraszülöttek esetén a szepszis rizikója emelkedik a születési súly csökkenésével. Anyag és módszer: A szerzők gyorsteszt segítségével 12 érett újszülött és 60 igen kis súlyú (VLBW) koraszülött interleukin-6-vérszintjét határozták meg a C-reaktív protein vizsgálatával egyidejűleg, akiket a Semmelweis Egyetem I. Számú Szülészeti és Nőgyógyászati Klinikájának Neonatális Intenzív Centrumában kezeltek 2005-ben és 2006-ban. A szérum-IL-6 meghatározása gyorsteszt segítségével történt (Milenia Quickline IL-6, PicoScan system). Eredmények: Vizsgálataikban a szérum-interleukin-6- és CRP-meghatározás korrelált. A szérum-IL-6-meghatározás szenzitivitása a CRP-értékkel együtt az általuk vizsgált betegcsoportban 100% volt, álnegatív eset nem fordult elő. A vizsgálat pozitív prediktív értéke 93%. Adataikat Mann–Whitney-teszt segítségével analizálták (SPSS Statistical Software Package, Chicago, IL, USA). Szignifikáns különbség volt az igazolt szepszis és az infekciós betegcsoport IL-6-értékei között ( p = 0,048), valamint az infekciós és nem infekciós csoport interleukin-6-értékei között ( p < 0,005). Következtetések: Az igen kis súlyúak nem specifikus infekciós tünetekhez hasonló reakcióit értékelve, a szeptikus és nem infekciós esetek elkülönítése a neonatális morbiditás és mortalitás csökkentése érdekében is fontos szempont, a költségek csökkentésével egyidejűleg.

The importance of the fetal origins of adult disease for geneticists

The purpose of this paper is to summarize some of the newly recognized in utero factors that interact with gene expression to establish the structural and physiologic processes that will serve the individual long term. These may be common to all mammals and probably reflect evolutionary plasticity, which improves species survival. The concepts of programming, fetal-maternal microchimerism, growth factors, and transgenerational nutritional affects are explored.

Placental lesions as predictors of cerebral palsy and abnormal neurocognitive function at school age in extremely low birth weight infants (<1 kg)

Extremely low birth weight (ELBW) infants (<1 kg) have high rates of neurodisability. Although previous studies have implicated placental lesions in adverse short-term neurologic outcomes in this population, none have assessed their effects in these children once they reach school age. We conducted a secondary analysis of placental pathology in a cohort study of inborn singleton ELBW infants born between 1992 and 1995 and evaluated for cerebral palsy (CP) and abnormal neurocognitive testing at 8 years of age (N = 129). The neurocognitive tests were the Kaufman Assessment Battery for Children (K-ABC) and 6 subtests of the NEPSY: A Developmental Neuropsychological Assessment. We found that placental lesions associated with maternal vascular underperfusion (increased syncytial knots and acute atherosis) were risk factors for CP, while villous edema was associated with low scores on both neurocognitive tests. Histologic chorioamnionitis (HCA) was not predictive of outcome in the population as a whole, but a severe fetal vascular response was associated with a lower NEPSY score in the subpopulation with HCA (N = 69). Placentas with increased syncytial knots, villous edema, and those with neither finding constituted nonoverlapping subgroups with distinct pathologic and perinatal characteristics. Among infants with villous edema (N = 25), those with neurologic impairment had lower gestational ages and more severe degrees of HCA. However, by logistic regression these other factors were not independent risk factors for abnormal neurocognitive testing, and only HCA with a severe fetal vascular response decreased the association of villous edema with low test scores for NEPSY, but not K-ABC.

Inflammation at birth and the insulin-like growth factor system in very preterm infants

BACKGROUND

Foetal inflammation is associated with an increased risk of brain damage in preterm infants whereas IGF-I is essential for cerebral development and exhibits anti-apoptotic properties.

AIM

To assess levels of IGF-I and IGF binding proteins at very preterm birth and to evaluate their relationship with foetal pro-inflammation and cerebral damage.

METHODS

Levels of IGF-I, IGF binding protein 3 (IGFBP-3), high- (hp) and low-phosphorylated (lp) IGFBP-1 in cord blood and neonatal blood at 72 h after delivery were analysed in relation to levels of cytokines and cerebral damage as detected by ultrasound in 74 inborn infants [mean gestational age (GA) 27.1 weeks]. Evaluation was performed separately according to birth weight for GA.

RESULTS

In cord blood of infants appropriate for gestational age (AGA) higher levels of IL-6 and IL-8 were associated with lower IGF-I (r =-0.38, p = 0.008 and r =-0.36, p = 0.014). Higher levels of IL-6, IL-8 and TNF-alpha were associated with both higher levels of lpIGFBP-1 (r = 0.54, p < 0.001, r = 0.50, p < 0.001 and r = 0.13, p = 0.012, respectively) and hpIGFBP-1 (r = 0.55, p < 0.001, r = 0.45, p = 0.002 and r = 0.32, p = 0.026, respectively). Infants with intraventricular haemorrhage grade III (n = 5) had higher levels of lp/hpIGFBP-1 in cord blood (p = 0.001 and 0.002, respectively).

CONCLUSION

Pro-inflammation at birth is associated with changes in the IGF-system. This may be of importance for development of brain damage in preterm infants.

The role of inflammation and infection in preterm birth

Inflammation has been implicated in the mechanisms responsible for preterm and term parturition, as well as fetal injury. Out of all of the suspected causes of preterm labor and delivery, infection and/or inflammation is the only pathological process for which both a firm causal link with preterm birth has been established and a molecular pathophysiology defined. Inflammation has also been implicated in the mechanism of spontaneous parturition at term. Most cases of histopathological inflammation and histological chorioamnionitis, both in preterm and term labor, are sub-clinical in nature. The isolation of bacteria in the amniotic fluid, known as microbial invasion of the amniotic cavity, is a pathological finding; the frequency of which is dependent upon the clinical presentation and gestational age. This article reviews the role of inflammation in preterm and term parturition.

Anti-inflammatory interventions in pregnancy: now and the future

A growing body of evidence implicates inflammatory pathways in adverse reproductive outcomes. This expanding evidence suggests that anti-inflammatory interventions may hold promise in reducing the maternal and neonatal morbidities and mortalities associated with these obstetrical complications. Preterm birth, preeclampsia, pregnancy loss and adverse neonatal outcomes have all been associated with the activation of inflammatory pathways during pregnancy. Because of the number of observational human studies, as well as animal models of preterm birth, the mechanisms by which inflammation may promote preterm parturition and adverse effects on the fetus are beginning to be elucidated. Although the future use of anti-inflammatory interventions in this context holds significant promise, much research is still warranted. Only when the pathogenesis of obstetrical complications is more fully understood can meaningful therapeutic interventions become a realistic goal.

Multiplexed protein measurement: technologies and applications of protein and antibody arrays

The ability to measure the abundance of many proteins precisely and simultaneously in experimental samples is an important, recent advance for static and dynamic, as well as descriptive and predictive, biological research. The value of multiplexed protein measurement is being established in applications such as comprehensive proteomic surveys, studies of protein networks and pathways, validation of genomic discoveries and clinical biomarker development. As standards do not yet exist that bridge all of these applications, the current recommended best practice for validation of results is to approach study design in an iterative process and to integrate data from several measurement technologies. This review describes current and emerging multiplexed protein measurement technologies and their applications, and discusses the remaining challenges in this field.