Chorioamnionitis, cortisol, and acute lung disease in very low birth weight infants

Epigenetic associations in HPA axis genes related to bronchopulmonary dysplasia and antenatal steroids

BACKGROUND

Bronchopulmonary dysplasia (BPD), a common morbidity among very preterm infants, is associated with chronic disease and neurodevelopmental impairments. A hypothesized mechanism for these outcomes lies in altered glucocorticoid (GC) activity. We hypothesized that BPD and its treatments may result in epigenetic differences in the hypothalamic-pituitary-adrenal (HPA) axis, which is modulated by GC, and could be ascertained using an established GC risk score and DNA methylation (DNAm) of HPA axis genes.

METHODS

DNAm was quantified from buccal tissue (ECHO-NOVI) and from neonatal blood spots (ELGAN ECHO) via the EPIC microarray. Prenatal maternal characteristics, pregnancy complication, and neonatal medical complication data were collected from medical record review and maternal interviews.

RESULTS

The GC score was not associated with steroid exposure or BPD. However, six HPA genes involved in stress response regulation demonstrated differential methylation with antenatal steroid exposure; two CpGs within FKBP5 and POMC were differentially methylated with BPD severity. These findings were sex-specific in both cohorts; males had greater magnitude of differential methylation within these genes.

CONCLUSIONS

These findings suggest that BPD severity and antenatal steroids are associated with DNAm at some HPA genes in very preterm infants and the effects appear to be sex-, tissue-, and age-specific.

IMPACT

This study addresses bronchopulmonary dysplasia (BPD), an important health outcome among preterm neonates, and interrogates a commonly studied pathway, the hypothalamic-pituitary-adrenal (HPA) axis. The combination of BPD, the HPA axis, and epigenetic markers has not been previously reported. In this study, we found that BPD itself was not associated with epigenetic responses in the HPA axis in infants born very preterm; however, antenatal treatment with steroids was associated with epigenetic responses.

High Expression of Adrenal Cortisol Synthases Is Acquired After Intrauterine Inflammation in Periviable Sheep Fetuses

Context

Intrauterine inflammation, a representative stressor for the fetus, has been shown to alter the hypothalamus-pituitary-adrenal (HPA) axis reactivity in preterm fetuses and increase postnatal cortisol production. However, the mechanism of this alteration has not yet been elucidated.

Objective

We aimed to clarify the effects of endotoxin-induced intrauterine inflammation on the HPA axis of periviable sheep fetuses.

Methods

Fetal sheep (0.63 term) were divided into 2 groups: (1) the endotoxin group, in which the endotoxin was injected into the amniotic fluid; and (2) the control group, in which the saline solution was injected instead. A corticotropin-releasing hormone (CRH) challenge test was performed on the third day after injection to evaluate the cortisol-producing capacity of each group. Gene expression levels in the fetal adrenal glands of each group were analyzed by RNA-seq.

Results

The cortisol levels were significantly higher in the endotoxin group than in the control group after CRH challenge (P = .02). There were no significant differences in the responsiveness of adrenocorticotropin and cortisone between the 2 groups. Gene expression levels of the following enzymes involved in cortisol synthesis were significantly elevated in the endotoxin group: cytochrome P450 family (CYP) 11 subfamily A member 1 (log2FC 1.75), CYP 17 subfamily A member 1 (log2FC 3.41), 3β-hydroxysteroid dehydrogenase type I (log2FC 1.13), steroidogenic acute regulatory protein (log2FC 1.09), and CYP 21 (log2FC 0.89).

Conclusion

Periviable fetuses exposed to inflammation in utero have altered the responsiveness of the HPA axis with increased expression of enzymes involved in cortisol synthesis in the adrenal gland.

Postnatal corticosteroid response in neonates < 32 weeks and relation with placental pathology

Acute chorioamnionitis and maternal vascular malperfusion are associated with an increased risk of bronchopulmonary dysplasia. To prevent bronchopulmonary dysplasia, postnatal corticosteroids are given to preterm neonates. Clinical observations indicate not all neonates respond to corticosteroids, the so-called non-responders. This study aimed to investigate the association between placental pathology and short-term response to postnatal corticosteroids in neonates < 32 weeks postconceptional age at risk for bronchopulmonary dysplasia. All neonates < 32 weeks born between 2009 and 2016, receiving corticosteroids in the course of BPD, were included. The preterm neonates were divided into three groups depending on placental histology: acute chorioamnionitis, maternal vascular malperfusion, or no placental pathology. Respiratory support was assessed prior to treatment and at days 4 and 7. A responder was defined as extubation within 7 days after starting corticosteroid treatment. In total, 52% of the chorioamnionitis neonates, 67% of the maternal vascular malperfusion neonates, and 58% of neonates in the no pathology group were responders. The odds ratio for extubation was 0.53 (0.18-1.55) at day 4 and 0.66 (0.23-1.97) at day 7, in the chorioamnionitis group compared to the maternal vascular malperfusion.

CONCLUSION

Short-term response to postnatal corticosteroids did not significantly differ between premature neonates born after acute chorioamnionitis, maternal vascular malperfusion, or no placenta pathology. However, a trend of better corticosteroid response in maternal vascular malperfusion neonates was found, potentially due to differences in prenatal pulmonary development and postnatal cortisol.

WHAT IS KNOWN

• Bronchopulmonary dysplasia is related to chorioamnionitis and maternal vascular malperfusion. • Corticosteroids remain an important treatment in the course of bronchopulmonary dysplasia despite conflicting results and non-responsiveness in some preterm neonates.

WHAT IS NEW

• Non-responsiveness might be related to differences in pulmonary inflammation and systemic cortisol due to predispositions triggered by chorioamnionitis or maternal vascular malperfusion. • Neonates born after maternal vascular malperfusion seem to respond better to postnatal corticosteroid treatment.

Intrauterine Inflammation Leads to Select Sex- and Age-Specific Behavior and Molecular Differences in Mice

Sex-specific differences in behavior have been observed in anxiety and learning in children exposed to prenatal inflammation; however, whether these behaviors manifest differently by age is unknown. This study assesses possible behavioral changes due to in utero inflammation as a function of age in neonatal, juvenile, and adult animals and presents potential molecular targets for observed differences. CD-1 timed pregnant dams were injected in utero with lipopolysaccharide (LPS, 50 μg/animal) or saline at embryonic day 15. No differences in stress responses were measured by neonatal ultrasonic vocalizations between LPS- and saline-exposed groups of either sex. By contrast, prenatal inflammation caused a male-specific increase in anxiety in mature but not juvenile animals. Juvenile LPS-exposed females had decreased movement in open field testing that was not present in adult animals. We additionally observed improved memory retrieval after in utero LPS in the juvenile animals of both sexes, which in males may be related to a perseverative phenotype. However, there was an impairment of long-term memory in only adult LPS-exposed females. Finally, gene expression analyses revealed that LPS induced sex-specific changes in genes involved in hippocampal neurogenesis. In conclusion, intrauterine inflammation has age- and sex-specific effects on anxiety and learning that may correlate to sex-specific disruption of gene expression associated with neurogenesis in the hippocampus.

Transplantation Mediates Much of the Racial Disparity in Survival from Childhood-onset Kidney Failure

Background: The role of kidney transplantation in differential survival in Black and White patients with childhood-onset kidney failure is unexplored. Methods: We analyzed 30-year cohort data of children beginning renal replacement therapy (RRT) before age 18 between January 1980 and December 2017 (n=28,337) in the U.S. Renal Data System. Cox regression identified transplant factors associated with survival by race. The survival mediational g-formula estimated the excess mortality among Black patients that could be eliminated if an intervention equalized their time with a transplant to that of White patients. Results: Black children comprised 24% of the cohort and their crude 30-year survival was 39% compared to 57% for White children (log rank p<0.001). Black children had 45% higher risk of death (adjusted hazard ratio (aHR) 1.45, 95% confidence interval (CI) 1.36, 1.54) and 31% lower incidence of first transplant (aHR 0.69, 95% CI 0.67, 0.72), and 39% lower incidence of second transplant (aHR 0.61, CI 0.57, 0.65). Children and young adults are likely to require multiple transplants, yet even after their first transplant, Black patients had 11% fewer total transplants (adjusted incidence rate ratio (aIRR) 0.89, 95% CI 0.86, 0.92). In Black patients grafts failed earlier after first and second transplants. Overall,Black patients spent 24% less of their RRT time with a transplant than did White patients (aIRR 0.76, 95% CI 0.74, 0.78). Transplantation compared with dialysis strongly protected against death (aHR 0.28, 95% CI 0.16, 0.48) by timevarying analysis. Mediation analyses estimated that equalizing transplant duration could prevent 35% (p<.001) of excess deaths in Black patients. Conclusions: Equalizing time with a functioning transplant for Black patients may equalize survival of childhood-onset ESRD with White patients.

Exposure to intrauterine inflammation and late-onset sepsis in very preterm infants

BACKGROUND

Late-onset sepsis is an important cause of mortality and morbidity in preterm infants. As these infants rely mostly on their innate immune system to fight off infection, enhancing this immune system by appropriate stimuli may prevent late-onset sepsis. However, it remains unclear which stimuli can enhance the neonatal immune system. This study aims to investigate the influence of intrauterine inflammation on late-onset sepsis.

METHODS

This is a retrospective cohort study in a Neonatal Intensive Care Unit in the Netherlands. Between 2005 and 2016, 1014 infants with ≤32 weeks gestational age and/or with a birth weight ≤1500 g were included. Intrauterine inflammation was subdivided into histological chorioamnionitis, fetal inflammatory response, and funisitis. Logistic and Cox regression analyses were performed to investigate the influence of intrauterine inflammation on late-onset sepsis.

RESULTS

Thirty-six percent of the included infants developed late-onset sepsis; 24% of placentas showed intrauterine inflammation. Late-onset sepsis incidence did not differ between infants with or without exposure to intrauterine inflammation after adjustment for gestational age (histological chorioamnionitis aHR 0.928 [CI: 0.727-1.185], p = 0.551; fetal inflammatory response aHR 1.011 [CI: 0.793-1.288], p = 0.930); funisitis aHR 0.965 [CI: 0.738-1.263], p = 0.797).

CONCLUSIONS

Late-onset sepsis in very preterm infants seems not to be associated with intrauterine inflammation.

IMPACT

Intrauterine inflammation is not protective of developing late-onset sepsis in premature infants. A large cohort study on the effect of intrauterine inflammation on neonatal outcome. This study adds to existing knowledge on finding appropriate stimuli to enhance the immune system of premature infants to improve neonatal outcome.

Absence of relationship between serum cortisol and critical illness in premature infants

BACKGROUND

Inadequate cortisol production in response to critical illness in extremely preterm infants may exacerbate poor outcomes. Despite commonly measuring cortisol concentration and administering hydrocortisone for presumed adrenal insufficiency, the relationship between serum cortisol concentration and illness severity remains unclear in this unique population.

OBJECTIVE

To determine the relationship between cortisol concentrations and illness severity as measured by the Score for Neonatal Acute Physiology II, neonatal Sequential Organ Failure Assessment and Vasoactive-Inotropic Score in premature infants.

DESIGN/METHODS

This retrospective, single-center cohort study included preterm infants born <30 weeks gestational age admitted to a level IV neonatal intensive care unit (NICU) between June 2011 and July 2018, who had a serum cortisol obtained for clinical indications before 36 weeks PMA. Demographic data were collected on infants and mothers. Nine clinical variables were identified a priori that could potentially modify cortisol concentration including critical illness. Univariate and multivariable analyses determined the relationship between cortisol concentration and each of these variables.

RESULTS

A total of 224 preterm infants with pretreatment serum cortisol concentration met criteria for inclusion. The median (IQR) gestational age at birth was 25 weeks (24, 26) and at cortisol measurement was 26 weeks (25, 28). The median cortisol was 13.3 ug/dL. Non-survivors had the highest values. Cortisol concentration did not correlate with any of the selected illness severity scores.

CONCLUSIONS

Cortisol concentrations in extremely preterm infants did not correlate with illness severity regardless of gestational age. Further studies are needed to identify clinically useful mediators of adrenal dysfunction and to guide clinical management.

Perinatal determinants of neonatal hair glucocorticoid concentrations

Adult hair glucocorticoid concentrations reflect months of hypothalamic-pituitary-adrenal axis activity. However, little is known about the determinants of neonatal hair glucocorticoids. We tested associations between perinatal exposures and neonatal hair glucocorticoids. Cortisol and cortisone were measured by LC-MS/MS in paired maternal and infant hair samples collected within 10 days of birth (n = 49 term, n = 47 preterm), with neonatal samples collected at 6-weeks in n = 54 preterm infants. We demonstrate cortisol accumulation in hair increases with fetal maturity, with hair cortisol being higher in term than preterm born infants after delivery (median 401 vs 106 pg/mg; p < 0.001). In term born infants, neonatal hair cortisol is positively associated with maternal hair cortisol concentration (β = 0.240, p = 0.045) and negatively associated with birthweight z-score (β = -0.340, p = 0.006). Additionally, being born without maternal labour is associated with lower hair cortisol concentrations (β = -0.489, p < 0.001) and a lower ratio of cortisol to cortisone (β = -0.484, p = 0.001). In preterm infants, histological chorioamnionitis is associated with a higher cortisol to cortisone ratio in hair (β = 0.459, p = 0.001). In samples collected 6 weeks after preterm birth, hair cortisol concentration is associated with cortisol hair concentrations measured after birth (β = 0.523, p < 0.001), chorioamnionitis (β = 0.250, p = 0.049) and postnatal exposures including intravenous hydrocortisone therapy (β = 0.343, p < 0.007) and neonatal sepsis (β = 0.290, p = 0.017). In summary, neonatal hair cortisol is associated with birth gestation, maternal hair cortisol concentration and fetal growth. Additionally, exposures at delivery are important determinants of hair cortisol, and should be considered in the design of future research investigating how neonatal hair cortisol relates to prenatal exposures or fetal development.

Glucocorticoids, sodium transport mediators, and respiratory distress syndrome in preterm infants

BACKGROUND

Antenatal glucocorticoids (GCs) reduce respiratory distress syndrome (RDS) in preterm infants and are associated with reduced lung liquid content. Our aim was to assess whether airway gene expression of mediators of pulmonary epithelial sodium and liquid absorption, and further, respiratory morbidity, associate with cord blood GC concentrations.

METHODS

The study included 64 infants delivered <32 weeks gestation. Cortisol and betamethasone in umbilical cord blood were quantified with liquid chromatography-tandem mass spectrometry. The total GC concentration was calculated. Gene expression of the epithelial sodium channel (ENaC), Na,K-ATPase, and serum- and GC-inducible kinase 1 at <2 h and at 1 day postnatally in nasal epithelial cell samples was quantified with reverse transcription-polymerase chain reaction. The mean oxygen supplementation during the first 72 h was calculated.

RESULTS

Concentrations of cord blood betamethasone and total GC were significantly lower in infants with RDS and correlated with mean oxygen supplementation. Expression of αENaC and α1- and β1Na,K-ATPase at <2 h correlated with betamethasone and total GC concentrations. Expression of Na,K-ATPase was lower in infants with RDS.

CONCLUSION

Enhancement of lung liquid absorption via increased expression of sodium transporters may contribute to the beneficial pulmonary effects of antenatal GCs.

IMPACT

RDS is related to lower umbilical cord blood GC concentrations and lower airway expression of sodium transporters. In addition to the timing of antenatal GC treatment, resulting concentrations may be of importance in preventing RDS. Induction of sodium transport may be a factor contributing to the pulmonary response to antenatal GCs.

Pathological staging of chorioamnionitis contributes to complications in preterm infants

Objective

To investigate the effect of pathological staging of chorioamnionitis (CA) on complications in preterm infants;

Methods

A single-center, retrospective study was conducted to choose singleton preterm infants (gestational age < 37 weeks) from the Department of Obstetrics and Gynecology in our hospital from December 2016 to December 2017. The basic data and placental pathological results were retrospectively collected. According to the placental pathological results of whether inflammation infiltrating amnion, CA 0/I phase was classified into non-amnionitis group, CA II/III phase was classified into amnionitis group, the incidence of common complications in preterm infants was compared. Further, logistic regression was used to analyze the effects of amnionitis on complications after being adjusted to gestational age, birth weight and thrombocytopenia.

Results

A total of 221 preterm infants were enrolled, including 186 cases in non-amnionitis group and 35 cases in amnionitis group. The gestational age of amnionitis group (32.00 ± 2.71 weeks) was significantly lower than non-amnionitis group (34.14 ± 2.06 weeks), birth weight (1.93 ± 0.64 kg) was significantly lower than that of non-amnionitis group (2.26 ± 0.58 kg), and the hospital stay in amnionitis group was significantly longer (25.71 ± 19.23 days), all of the difference above was statistically significant(P < 0.05). The incidence of intraventricular hemorrhage (IVH) in amnionitis group (37.14%) was significantly higher than that in non-amnionitis group (13.98%) (P = 0.002), and the risk of IVH was significantly increased by amnionitis (OR = 3.636, 95%CI: 1.632–8.102); after correction of gestational age, birth weight and thrombocytopenia, the risk of IVH was still significantly increased (OR = 2.471, P = 0.046, 95% CI: 1.015–6.015). And the late-onset IVH was more common (P = 0.009).

Conclusion

Amnionitis leads to a significant reduction in gestational age and birth weight in preterm infants, and it is an independent risk factor for IVH.

Prenatal opioid exposure: The next neonatal neuroinflammatory disease

The rates of opioid use disorder during pregnancy have more than quadrupled in the last decade, resulting in numerous infants suffering exposure to opioids during the perinatal period, a critical period of central nervous system (CNS) development. Despite increasing use, the characterization and definition of the molecular and cellular mechanisms of the long-term neurodevelopmental impacts of opioid exposure commencing in utero remains incomplete. Thus, in consideration of the looming public health crisis stemming from the multitude of infants with prenatal opioid exposure entering school age, we undertook an investigation of the effects of perinatal methadone exposure in a novel preclinical model. Specifically, we examined the effects of opioids on the developing brain to elucidate mechanisms of putative neural cell injury, to identify diagnostic biomarkers and to guide clinical studies of outcome and follow-up. We hypothesized that methadone would induce a pronounced inflammatory profile in both dams and their pups, and be associated with immune system dysfunction, sustained CNS injury, and altered cognition and executive function into adulthood. This investigation was conducted using a combination of cellular, molecular, biochemical, and clinically translatable biomarker, imaging and cognitive assessment platforms. Data reveal that perinatal methadone exposure increases inflammatory cytokines in the neonatal peripheral circulation, and reprograms and primes the immune system through sustained peripheral immune hyperreactivity. In the brain, perinatal methadone exposure not only increases chemokines and cytokines throughout a crucial developmental period, but also alters microglia morphology consistent with activation, and upregulates TLR4 and MyD88 mRNA. This increase in neuroinflammation coincides with reduced myelin basic protein and altered neurofilament expression, as well as reduced structural coherence and significantly decreased fractional anisotropy on diffusion tensor imaging. In addition to this microstructural brain injury, adult rats exposed to methadone in the perinatal period have significant impairment in associative learning and executive control as assessed using touchscreen technology. Collectively, these data reveal a distinct systemic and neuroinflammatory signature associated with prenatal methadone exposure, suggestive of an altered CNS microenvironment, dysregulated developmental homeostasis, complex concurrent neural injury, and imaging and cognitive findings consistent with clinical literature. Further investigation is required to define appropriate therapies targeted at the neural injury and improve the long-term outcomes for this exceedingly vulnerable patient population.

Early Second Trimester Maternal Serum Steroid-Related Biomarkers Associated with Autism Spectrum Disorder

Epidemiologic studies link increased autism spectrum disorder (ASD) risk to obstetrical conditions associated with inflammation and steroid dysregulation, referred to as prenatal metabolic syndrome (PNMS). This pilot study measured steroid-related biomarkers in early second trimester maternal serum collected during the first and second trimester evaluation of risk study. ASD case and PNMS exposure status of index offspring were determined through linkage with autism registries and birth certificate records. ASD case (N = 53) and control (N = 19) groups were enriched for PNMS exposure. Higher estradiol and lower sex hormone binding globulin (SHBG) were significantly associated with increased ASD risk. Study findings provide preliminary evidence to link greater placental estradiol activity with ASD and support future investigations of the prenatal steroid environment in ASD.

Hydrocortisone and bronchopulmonary dysplasia: variables associated with response in premature infants

OBJECTIVE

The primary objective was to evaluate hydrocortisone's efficacy for decreasing respiratory support in premature infants with developing bronchopulmonary dysplasia (BPD). Secondary objectives included assessment of the impact of intrauterine growth restriction (IUGR), maternal history of chorioamnionitis, side effects and route of administration associated with hydrocortisone's efficacy. Dexamethasone as second-line treatment to decrease respiratory support was reviewed.

METHODS

Retrospective chart review of preterm infants requiring respiratory support receiving hydrocortisone.

RESULTS

A total of 48 patients were included. Successful extubation was achieved in 50% of intubated patients after hydrocortisone treatment with no major complications. In our small study, history of maternal chorioamnionitis, IUGR or route of administration did not affect the response. Rescue dexamethasone after hydrocortisone therapy was ineffective in the ten patients who failed extubation following hydrocortisone.

CONCLUSION

Hydrocortisone is effective in decreasing respiratory support in patients with developing BPD without major complications. Randomized studies are warranted to confirm our findings.

Histological chorioamnionitis, antenatal steroids, and neonatal outcomes in very low birth weight infants: A nationwide study

Background

The aim of this study was to investigate whether some associations between histological chorioamnionitis (HCA) and favorable neonatal outcomes might be linked to those of antenatal steroids (AS) by determining the separate as well as the combined associations of HCA and AS with neonatal outcomes in very low birth weight infants (VLBWIs).

Methods

This was a population-based study of VLBWIs born at 20–33 weeks’ gestation between January 2013 and December 2015 from the Korean Neonatal Network. A total of 4652 VLBWIs were enrolled for prevalence study. Of these, 2900 singleton VLBWIs were used for outcome analyses to evaluate individual associations of HCA and AS simultaneously with correction for potential perinatal factors and an interaction term of HCA and AS.

Results

The overall prevalence of HCA was 34.9% (1623 VLBWIs). Multivariable logistic regression demonstrated that HCA was associated with decreased mortality (adjusted odds ratio [aOR], 0.51; 95% confidence interval [CI], 0.29–0.91; P = 0.022), AS were associated with reduction in mortality (aOR, 0.59; 95% CI, 0.39–0.90; P = 0.014) and neonatal seizure (aOR, 0.57; 95% CI, 0.37–0.86; P = 0.008), and a combination of HCA and AS was associated with remarkably lowered severe intraventricular hemorrhage by interacting with each other (aOR, 0.47; 95% CI, 0.25–0.88; P = 0.019).

Conclusions

We suggest that in VLBWIs HCA and AS may be favorable independent factors for neonatal outcome and may also work in synergy for neuroprotection.

The Associations between Antenatal Corticosteroids and In-Hospital Outcomes of Preterm Singleton Appropriate for Gestational Age Neonates according to the Presence of Maternal Histologic Chorioamnionitis

INTRODUCTION

This study aimed to assess the association between antenatal corticosteroid (ACS) and in-hospital outcomes of preterm singleton appropriate for gestational age (AGA) infants according to the presence of maternal histologic chorioamnionitis (HCA).

METHODS

A retrospective study was performed with singleton AGA neonates of 23+0 to 33+6 weeks' gestation born between 2007 and 2014. We compared the clinical outcomes according to the presence of HCA and ACS use. We also divided the ACS group into 2 groups: infants who received ACS 2-7 days before birth (optimal ACS) or not (suboptimal ACS). Multivariate logistic regression with Firth's penalized likelihood was performed.

RESULTS

In total, 254 neonates were eligible with 109 neonates with HCA (42.9%). In multivariate analysis adjusting for GA, sex, and cesarean section, ACS use was associated with reduced severe bronchopulmonary dysplasia (BPD) or death and hypotension within 7 postnatal days among the neonates with HCA. However, it was associated with increased patent ductus arteriosus (PDA) treatment. In the optimal ACS group, severe BPD or death (aOR 0.03, 95% CI 0.01-0.42), hypotension (aOR 0.02, 95% CI 0.01-0.26), and inhaled nitric oxide use (aOR 0.06, 95% CI 0.00-0.81) were lower, however, PDA treatment (aOR 8.14, 95% CI 1.20-55.24) and sepsis (aOR 6.85, 95% CI 1.02-46.07) were higher when compared with the no ACS group among HCA+ infants. Among HCA- infants, only PDA treatment was lower in the ACS group.

CONCLUSION

In neonates with HCA, ACS treatment was associated with reduced morbidities. However, increased sepsis was associated with optimal ACS use.

Repetitive Neonatal Erythropoietin and Melatonin Combinatorial Treatment Provides Sustained Repair of Functional Deficits in a Rat Model of Cerebral Palsy

Cerebral palsy (CP) is the leading cause of motor impairment for children worldwide and results from perinatal brain injury (PBI). To test novel therapeutics to mitigate deficits from PBI, we developed a rat model of extreme preterm birth (<28 weeks of gestation) that mimics dual intrauterine injury from placental underperfusion and chorioamnionitis. We hypothesized that a sustained postnatal treatment regimen that combines the endogenous neuroreparative agents erythropoietin (EPO) and melatonin (MLT) would mitigate molecular, sensorimotor, and cognitive abnormalities in adults rats following prenatal injury. On embryonic day 18 (E18), a laparotomy was performed in pregnant Sprague–Dawley rats. Uterine artery occlusion was performed for 60 min to induce placental insufficiency via transient systemic hypoxia-ischemia, followed by intra-amniotic injections of lipopolysaccharide, and laparotomy closure. On postnatal day 1 (P1), approximately equivalent to 30 weeks of gestation, injured rats were randomized to an extended EPO + MLT treatment regimen, or vehicle (sterile saline) from P1 to P10. Behavioral assays were performed along an extended developmental time course (n = 6–29). Open field testing shows injured rats exhibit hypermobility and disinhibition and that combined neonatal EPO + MLT treatment repairs disinhibition in injured rats, while EPO alone does not. Furthermore, EPO + MLT normalizes hindlimb deficits, including reduced paw area and paw pressure at peak stance, and elevated percent shared stance after prenatal injury. Injured rats had fewer social interactions than shams, and EPO + MLT normalized social drive. Touchscreen operant chamber testing of visual discrimination and reversal shows that EPO + MLT at least partially normalizes theses complex cognitive tasks. Together, these data indicate EPO + MLT can potentially repair multiple sensorimotor, cognitive, and behavioral realms following PBI, using highly translatable and sophisticated developmental testing platforms.

Inflammation-induced preterm lung maturation: lessons from animal experimentation

Intrauterine inflammation, or chorioamnionitis, is a major contributor to preterm birth. Prematurity per se is associated with considerable morbidity and mortality resulting from lung immaturity but exposure to chorioamnionitis reduces the risk of neonatal respiratory distress syndrome (RDS) in preterm infants. Animal experiments have identified that an increase in pulmonary surfactant production by the preterm lungs likely underlies this decreased risk of RDS in infants exposed to chorioamnionitis. Further animal experimentation has shown that infectious or inflammatory agents in amniotic fluid exert their effects on lung development by direct effects within the developing respiratory tract, and probably not by systemic pathways. Differences in the effects of intrauterine inflammation and glucocorticoids demonstrate that canonical glucocorticoid-mediated lung maturation is not responsible for inflammation-induced changes in lung development. Animal experimentation is identifying alternative lung maturational pathways, and transgenic animals and cell culture techniques will allow identification of novel mechanisms of lung maturation that may lead to new treatments for the prevention of RDS.

Morbidity in preterm infants with fetal inflammatory response syndrome

BACKGROUND

The aim of this study was to evaluate the relationship between umbilical cord blood interleukin (IL)-6 concentration and preterm morbidity and mortality in premature infants born with fetal inflammatory response syndrome (FIRS).

METHODS

This prospective, observational study included 84 preterm infants with a gestational age of 24-36 weeks who had been admitted to the neonatal intensive care unit (NICU). FIRS was defined as umbilical cord blood IL-6 > 11 pg/mL. In premature infants with FIRS, morbidities (multiple organ failure [MOF], respiratory distress syndrome [RDS], patent ductus arteriosus, intraventricular hemorrhage, bronchopulmonary dysplasia, retinopathy of prematurity) and death were evaluated. Critical umbilical cord blood IL-6 concentrations for the development of RDS, death, and for MOF were determined in premature infants with FIRS.

RESULTS

Fifty-two infants with IL-6 concentration > 11 pg/mL constituted the FIRS group. Thirty-two infants without FIRS served as a control group. RDS, MOF, and mortality were significantly higher in the FIRS group (P = 0.001, P = 0.001, and P = 0.005, respectively). Umbilical cord blood IL-6 concentration > 26.7 pg/mL in the FIRS group was found to be predictive of RDS, with 70% sensitivity and 85% specificity. Umbilical cord blood IL-6 concentration > 37.7 pg/mL was found to be predictive of death, with 78.6% sensitivity and 60% specificity. The predictive value of IL-6 for the development of MOF was 17.5 pg/mL, with 91% sensitivity and 66% specificity.

CONCLUSIONS

Umbilical cord blood IL-6 concentration > 26.7, 37.7, and 17.5 pg/mL in premature infants with FIRS was found to be predictive for RDS, death, and MOF, respectively.

Ventilation-induced lung injury is not exacerbated by growth restriction in preterm lambs

Intrauterine growth restriction (IUGR) and preterm birth are frequent comorbidities and, combined, increase the risk of adverse respiratory outcomes compared with that in appropriately grown (AG) infants. Potential underlying reasons for this increased respiratory morbidity in IUGR infants compared with AG infants include altered fetal lung development, fetal lung inflammation, increased respiratory requirements, and/or increased ventilation-induced lung injury. IUGR was surgically induced in preterm fetal sheep (0.7 gestation) by ligation of a single umbilical artery. Four weeks later, preterm lambs were euthanized at delivery or delivered and ventilated for 2 h before euthanasia. Ventilator requirements, lung inflammation, early markers of lung injury, and morphological changes in lung parenchymal and vascular structure and surfactant composition were analyzed. IUGR preterm lambs weighed 30% less than AG preterm lambs, with increased brain-to-body weight ratio, indicating brain sparing. IUGR did not induce lung inflammation or injury or alter lung parenchymal and vascular structure compared with AG fetuses. IUGR and AG lambs had similar oxygenation and respiratory requirements after birth and had significant, but similar, increases in proinflammatory cytokine expression, lung injury markers, gene expression, and surfactant phosphatidylcholine species compared with unventilated controls. IUGR does not induce pulmonary structural changes in our model. Furthermore, IUGR and AG preterm lambs have similar ventilator requirements in the immediate postnatal period. This study suggests that increased morbidity and mortality in IUGR infants is not due to altered lung tissue or vascular structure, or to an altered response to early ventilation.

Postnatal Infections and Immunology Affecting Chronic Lung Disease of Prematurity

Premature infants suffer significant respiratory morbidity during infancy with long-term negative consequences on health, quality of life, and health care costs. Enhanced susceptibility to a variety of infections and inflammation play a large role in early and prolonged lung disease following premature birth, although the mechanisms of susceptibility and immune dysregulation are active areas of research. This article reviews aspects of host-pathogen interactions and immune responses that are altered by preterm birth and that impact chronic respiratory morbidity in these children.

A mass shooting at Port Arthur, Tasmania, Australia: a study of its impact on early pregnancy losses using a conception time-based methodology

STUDY QUESTION

Does an acute calamity in a community cause early miscarriage and is this association the same for male and female fetuses?

SUMMARY ANSWER

Estimated losses of 29.5% of first trimester pregnancies in the affected region could be associated with an acute calamity, with no statistically significant difference in estimated losses by fetal sex.

WHAT IS KNOWN ALREADY

There are very few studies on the impact of a calamity on early pregnancy loss and its differential effects on male and female fetuses. A decline in the human sex ratio at birth associated with the events of 9/11 in New York has been documented.

STUDY DESIGN, SIZE, DURATION

This is a retrospective descriptive study of birth register data in Tasmania, Australia, from 1991 to 1997, covering the period in which the calamity occurred. The register contains data on all pregnancies that proceeded to >20 weeks gestation. The conception date was calculated by subtracting gestational age from birth date. We estimated that 40 318 pregnancies were conceived in the period 1991-1996 inclusive. These were aggregated to 4-weekly blocks classified by region and sex.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The acute calamity was at Port Arthur, Tasmania, Australia. On 28 April 1996, a gunman opened fire on visitors and staff in a tourist cafe. A very stressful 20 h period, ended with 35 people dead and 22 injured. A negative binomial regression model was used to assess the association between this calamity and pregnancy loss. This loss is evidenced by a shortfall in the registration of pregnancies that were in their first trimester at the time of the calamity.

MAIN RESULTS AND THE ROLE OF CHANCE

We estimated a shortfall of 29.5% or 229 registered pregnancies among those in the first trimester at the time of the calamity (P < 0.001), in the region surrounding the calamity site. There was no sex effect in this shortfall (P = 0.911). There was no corresponding shortfall in other parts of Tasmania (P = 0.349).

LIMITATIONS, REASONS FOR CAUTION

The study is descriptive and cannot produce causal inferences. These first trimester miscarriages are estimated statistically and it is understood that gestational age is an estimate. The use of maternal residential postcodes at birth as a surrogate for geographic area or space assumes that the mother has not moved into the postcode area after the calamity and before the reporting of a birth.

WIDER IMPLICATIONS OF THE FINDINGS

The results of this study suggest that calamities bring about significant pregnancy loss affecting both sexes. The methodology presented of inferring conception date from birth date and using this for analysis, provides a more accurate assessment of first trimester pregnancy losses than raw birth data or sex ratio at birth.

Adrenal and thyroid function in the fetus and preterm infant

Adrenal and thyroid hormones are essential for the regulation of intrauterine homeostasis, and for the timely differentiation and maturation of fetal organs. These hormones play complex roles during fetal life, and are believed to underlie the cellular communication that coordinates maternal-fetal interactions. They serve to modulate the functional adaptation for extrauterine life during the perinatal period. The pathophysiology of systemic vasopressor-resistant hypotension is associated with low levels of circulating cortisol, a result of immaturity of hypothalamic-pituitary-adrenal axis in preterm infants under stress. Over the past few decades, studies in preterm infants have shown abnormal clinical findings that suggest adrenal or thyroid dysfunction, yet the criteria used to diagnose adrenal insufficiency in preterm infants continue to be arbitrary. In addition, although hypothyroidism is frequently observed in extremely low gestational age infants, the benefits of thyroid hormone replacement therapy remain controversial. Screening methods for congenital hypothyroidism or congenital adrenal hyperplasia in the preterm neonate are inconclusive. Thus, further understanding of fetal and perinatal adrenal and thyroid function will provide an insight into the management of adrenal and thyroid function in the preterm infant.

Parenteral Nutrition-Associated Cholestasis in Premature Infants: Role of Macronutrients

PURPOSE

To evaluate whether intravenous lipid (IL) intake is associated with the development of parenteral nutrition-associated cholestasis (PNAC) in infants younger than 32 weeks gestational age (GA).

METHODS

A retrospective matched case-control study (1:1) was performed including infants younger than 32 weeks GA admitted to the neonatal intensive care unit within 48 hours after birth. Infants with a chromosomal disorder, TORCH infection (toxoplasmosis, syphilis, rubella, cytomegalovirus, herpes, human immunodeficiency virus, and parvovirus), metabolic disorder, and/or surgical abnormality of the hepatobiliary system were excluded. Infants with PNAC (direct bilirubin 2 mg/dL or higher) comprised the case group, while infants without PNAC comprised the control group. Duration of parenteral nutrition, intravenous fluid intake on the day of development of PNAC, and GA were used as matching criteria.

RESULTS

A total of 46 subjects were studied. Daily average intravenous dextrose (ID) intake was significantly higher in infants with PNAC compared with infants without PNAC (12.72 ± 2.5 g/kg/d and 10.64 ± 2.1 g/kg/d, respectively, P = .004). On comparison of receiver operating characteristic curves, the area under the curve for ID intake (0.74) was significantly higher (P = .01) compared with the area under the curve for IL intake (0.59) and intravenous protein (IP) intake (0.52). On logistic regression, daily ID intake was associated with PNAC (odds ratio 1.7; 95% CI, 1.04-2.9, P = .03) after controlling for daily IP and IL intake.

CONCLUSIONS

ID intake may be associated with the development of PNAC in premature infants. Our findings suggest that limiting ID intake may be more useful than limiting IL intake in reducing the incidence of PNAC in premature infants.

Population pharmacokinetics of unbound hydrocortisone in critically ill neonates and infants with vasopressor-resistant hypotension

OBJECTIVES

To determine the population pharmacokinetics of unbound hydrocortisone in critically ill neonates and infants receiving IV hydrocortisone for treatment of vasopressor-resistant hypotension and to identify patient-specific sources of pharmacokinetic variability.

DESIGN

Prospective observational cohort study.

SETTING

Level 3 neonatal ICU.

PATIENTS

Sixty-two critically ill neonates and infants receiving IV hydrocortisone as part of standard of care for the treatment of vasopressor-resistant hypotension: median gestational age 28 weeks (range, 23-41), median weight 1.2 kg (range, 0.5-4.4), and 29 females.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Unbound baseline cortisol and postdose hydrocortisone concentrations measured from blood samples being drawn for routine laboratory tests. A one-compartment model best described the data. Allometric weight and postmenstrual age were significant covariates on unbound hydrocortisone clearance and volume of distribution. Final population estimates for clearance, volume of distribution, and baseline cortisol concentration were 20.2 L/hr, 244 L, and 1.37 ng/mL, respectively. Using the median weight and postmenstrual age of our subjects (i.e., 1.2 kg and 28 wk) in the final model, the typical unbound hydrocortisone clearance and volume of distribution were 1.0 L/hr and 4.2 L, respectively. The typical half-life for unbound hydrocortisone was 2.9 hours. A sharp and continuous increase in unbound hydrocortisone clearance was observed at 35 weeks postmenstrual age.

CONCLUSIONS

We report the first pharmacokinetic data for unbound hydrocortisone, the pharmacologically active moiety, in critically ill neonates and infants with vasopressor-resistant hypotension. Unbound hydrocortisone clearance increased with body weight and was faster in children with an older postmenstrual age. Unbound hydrocortisone clearance increased sharply at 35 weeks postmenstrual age and continued to mature thereafter. This study lays the groundwork for evaluating unbound hydrocortisone exposure-response relationships and drawing definitive conclusions about the dosing of IV hydrocortisone in critically ill neonates and infants with vasopressor-resistant hypotension.

Chorioamnionitis in the pathogenesis of brain injury in preterm infants

Chorioamnionitis (or placental infection) is suspected to be a risk factor for brain injury in premature infants. The suggested association between chorioamnionitis and cystic periventricular leukomalacia and cerebral palsy is uncertain because of the variability of study designs and definitions of chorioamnionitis. Improvements in neonatal intensive care may have attenuated the impact of chorioamnionitis on brain health outcomes. Large multicenter studies using rigorous definitions of chorioamnionitis on placental pathologies and quantitative magnetic resonance techniques may offer the optimal way to clarify the complex role of chorioamnionitis in modifying brain health and long-term outcomes.

Effects of placental inflammation on neonatal outcome in preterm infants

BACKGROUND

Intrauterine infection is the most commonly identified cause of preterm birth. In this study, our aim was to determine the association between placental inflammation and neonatal outcome in a prospective observational cohort of preterm infants of less than 34 weeks gestational age. We especially focused on the distinct effects of maternal inflammatory response (MIR) with and without fetal inflammatory response (FIR).

METHODS

Clinical characteristics and placental histological results were prospectively collected from 216 singleton infants born at a gestational age of less than 34 weeks.

RESULTS

Of the 216 newborns, 104 (48.1%) infants had histological placental inflammation. Based on their pathological findings, the premature infants were divided into three groups: (1) the MIR negative-FIR negative (MIR-FIR-) group; (2) the MIR positive-FIR positive (MIR+FIR+) group; and (3) the MIR positive-FIR negative (MIR+FIR-) group. The incidence of neonatal respiratory distress syndrome (RDS) in the MIR+FIR- group (5.7%) and in the MIR+FIR+ group (2.0%) was significantly lower than in the MIR-FIR- group (19.6%) (p < 0.05). Logistic regression analysis showed that MIR+FIR+ group had a decreased incidence of neonatal RDS (OR = 0.076; 95% CI 0.009-0.624; p = 0.016). The incidence of intraventricular hemorrhage (IVH) Grade 2 or greater was significantly higher in the MIR+FIR+ group (42.3%) than in the MIR+FIR- group (13.0%) (p < 0.05) or in the MIR-FIR- group (15.2%) (p < 0.05). Logistic regression analysis also showed that MIR+FIR+ was associated with an increased incidence of IVH Grade 2 or greater (OR = 4.08; 95% CI 1.259-13.24; p = 0.019).

CONCLUSION

A positive MIR in association with a positive FIR decreases the risk of RDS, but increases the risk of IVH Grade 2 or greater in preterm infants with a gestational age of less than 34 weeks. However, a positive MIR alone has little effect on neonatal outcome.

Prenatal and postnatal inflammation in relation to cortisol levels in preterm infants at 18 months corrected age

OBJECTIVE

To examine whether early inflammation is related to cortisol levels at 18 months corrected age (CA) in children born very preterm.

STUDY DESIGN

Infants born ≤ 32 weeks of gestational age were recruited in the neonatal intensive care unit (NICU), and placental histopathology, magnetic resonance imaging (MRI) and chart review were obtained. At 18 months CA, developmental assessment and collection of three salivary cortisol samples were carried out. Generalized least squares was used to analyze data from 85 infants providing 222 cortisol samples.

RESULT

Infants exposed to chorioamnionitis with funisitis had a significantly different pattern of cortisol across the samples compared with infants with chorioamnionitis alone or no prenatal inflammation (F(4, 139)=7.3996, P<0.0001). Postnatal infections, necrotizing enterocolitis and chronic lung disease were not significantly associated with the cortisol pattern at 18 months CA.

CONCLUSION

In children born very preterm, prenatal inflammatory stress may contribute to altered programming of the hypothalamic-pituitary-adrenal (HPA) axis.

Neonatal outcome of preterm infants born to mothers with abnormal genital tract colonisation and chorioamnionitis: a cohort study

PURPOSE

We hypothesised that abnormal genital tract colonisation leading to an in utero inflammation/infection process, contributes to the risk of respiratory distress syndrome (RDS), patent ductus arteriosus (PDA), intra ventricular haemorrhage (IVH), bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP) and necrotizing enterocolitis (NEC) in preterm infants.

METHODS

396 placentas and umbilical cords of neonates born at 22-32weeks of gestation were evaluated. Genital tract and amniotic fluid swabs were cultured for aerobic and anaerobic bacteria.

RESULTS

Chorioamnionitis significantly increases the risk for RDS (OR 1.74, 95% CI 1.14-2.65), NEC (OR 3.22, 95% CI 1.36-3.28) and ROP>2 (OR 2.12, 95% CI 1.33-3.36). But the risk for IVH, PDA and BPD did not differ between the groups. Klebsiella pneumoniae (OR 5.33, 95% CI 1.06-26.79), Staphylococcus sp. (OR 18.39, 95% CI 2.32-145.2) and Enterococcus faecalis (OR 10.7, 95% CI 1.27-89.9) showed a significant relationship with intrauterine inflammation processes. E. faecalis increased the risk for NEC (OR 6.13, 95% CI 1.059-37.6). We did not note a link between ROP and genital tract colonisation. Interestingly PDA seems to be triggered by the presence of Pseudomonas aeruginosa (OR 2.38 95% CI 1.83-3.82).

CONCLUSION

Our results show a link between K. pneumoniae, Staphylococcus sp., E. faecalis and intrauterine infection. E. faecalis increases the risk for NEC, and suggests a direct link between gram + bacteria, chorioamnionitis and NEC.

Physiology of transition from intrauterine to extrauterine life

The transition from fetus to newborn is the most complex adaptation that occurs in human experience. Lung adaptation requires coordinated clearance of fetal lung fluid, surfactant secretion, and onset of consistent breathing. The cardiovascular response requires striking changes in blood flow, pressures, and pulmonary vasodilation. Energy metabolism and thermoregulation must be quickly controlled. The primary mediators that prepare the fetus for birth and support the multiorgan transition are cortisol and catecholamine. Abnormalities in adaptation are frequently found following preterm birth or cesarean delivery at term, and many of these infants need delivery room resuscitation to assist in this transition.

High tissue factor in lungs and plasma associates with respiratory morbidity in preterm infants

AIM

In preterm infants, inflammation and intra-alveolar fibrin formation characterize respiratory distress syndrome (RDS). Tissue factor (TF) is a link between inflammation and coagulation pathways. We investigated the relationship between TF and cytokines in preterm infants to gain information of the role of TF in the inflammatory response.

METHODS

We measured TF in plasma and in tracheal aspirates and analysed TF on monocytes by flow cytometry and 13 cytokines from plasma, in 56 preterm infants (birthweight 600-1500 g) during their first week.

RESULTS

Plasma TF increased and peaked on day 3 and correlated with both RDS and inversely with paO2/FIO2. On day 1, TF in tracheal aspirates was 10-fold higher than in plasma and correlated with plasma TF (4888 vs. 506 pg/mL, R = 0.692, p = 0.013, n = 12). Of main pro-inflammatory cytokines, plasma TF correlated post-natally with IL-8 and IL-6 but not with IL-1 or TNF-α.

CONCLUSIONS

Respiratory morbidity associates with high TF in lungs and plasma. In sick newborn infants, upregulation of TF may be mediated by IL-6 and IL-8. High TF and pro-inflammatory cytokines may together participate in the pathogenesis of pulmonary and extrapulmonary injury in preterm infants through pro-inflammatory mechanisms.

A prospective longitudinal study to estimate the "adjusted cortisol percentile" in preterm infants

The normal range of serum cortisol concentrations and the appropriate levels of circulating cortisol in different clinical situations in preterm infants are not well defined. This study aimed to evaluate the impact of perinatal factors on circulating cortisol levels in preterm infants and to create a quantitative model that could estimate the "adjusted cortisol percentile." Serial serum cortisol concentrations were measured in 209 infants ≤ 32 wk gestation on d 1, 4, 7, 14, and 21 of life. Seven perinatal factors or conditions that could affect circulating cortisol level were identified. Serum cortisol levels were higher on d 4 (p = 0.007) and d 7 (p = 0.007) but lower on d 21 (p = 0.001) compared with d 1. Serum cortisol was also higher in infants on nasal continuous positive airway pressure (p = 0.003); requiring a second vasopressor (p < 0.001); with intraventricular hemorrhage (≥ grade 3; p < 0.001); with histologic chorioamnionitis (p = 0.007); with severe lung disease (p = 0.046); and with decreasing GA (p < 0.001). A mathematical equation was proposed based on factors derived in this preliminary study for estimating the adjusted cortisol percentile. Frontline neonatologists could now access the equation on our Web site (http://www.sta.cuhk.edu.hk/pswong/ACortP.html) to calculate the adjusted cortisol percentile, which could potentially improve the interpretation of circulating cortisol in different clinical situations.

Neonatal and neurodevelopmental outcomes of very low birth weight infants with histologic chorioamnionitis

OBJECTIVE

To determine survival and neurodevelopmental outcomes at 18 months corrected age among very low birth weight infants ≤ 32 weeks gestation with histologic chorioamnionitis.

STUDY DESIGN

Observational, regionalized, single-center cohort study with prospective follow-up.

RESULTS

Of the 628 infants meeting the selection criteria, 303 (48%) were born to mothers with evidence of histologic chorioamnonitis. Neonates with histologic chorioamnonitis were of lower gestational age and birth weight. On univariate analysis, they were more likely to have hypotension, bronchopulmonary dysplasia, severe intraventricular hemorrhage, severe retinopathy of prematurity, early-onset sepsis, and death. Infants with histologic chorioamnonitis were more likely to have any neurodevelopmental impairment, specifically, mental delay with a lower mental developmental index. When adjusting for perinatal variables, histologic chorioamnonitis had a protective effect on mortality rates (adjusted OR = 0.44, 95% CI: 0.24-0.8; P = .01; n = 619), had a nonsignificant effect on neurodevelopmental impairment (adjusted odds ratio = 1.33, 95% CI: 0.82-2.17; P = .25; n = 496), and was associated with a 4-point lower mental developmental index at 18-months follow-up (adjusted difference -3.93, 95% CI: -7.52 to -0.33; P = .03; n = 496).

CONCLUSIONS

Although infants with histologic chorioamnonitis were at an increased risk for death and neurodevelopmental impairment, after multivariate analyses, histologic chorioamnonitis was not associated with adverse long-term outcomes. Results suggest fetal protection from treatment-responsive maternal infection and inflammation.

Chorioamnionitis: a multiorgan disease of the fetus?

The bacterial infection of chorion and amnion is a common finding in premature delivery and is referred to as chorioamnionitis. As the mother rarely shows symptoms of a systemic inflammation, the course of chorioamnionitis is frequently asymptomatic and chronic. In contrast, the fetal inflammatory response syndrome represents a separate phenomenon, including umbilical inflammation and increased serum levels of proinflammatory cytokines in the fetus. Ascending maternal infections frequently lead to systemic fetal inflammatory reaction. Clinical studies have shown that antenatal exposure to inflammation puts the extremely immature neonates at a high risk for worsening pulmonary, neurological and other organ development. Interestingly, the presence of chorioamnionitis is associated with a lower rate of neonatal mortality in extremely immature newborns. In the following review, the pathogeneses of inflammation-associated perinatal morbidity are outlined. The concept of fetal multiorganic disease during intrauterine infection is introduced and discussed.

Chorioamnionitis alters the response to surfactant in preterm infants

OBJECTIVE

To study the association between antenatal exposure to chorioamnionitis and the neonatal response to surfactant.

STUDY DESIGN

Prospective observational cohort of 301 preterm infants of gestational age < or = 32.0 weeks, 146 of whom received surfactant according to standardized criteria. Fraction of inspired oxygen (FiO(2)) requirement (using analysis of variance) and time to extubation (using Kaplan-Meier and Cox regression analyses) were compared between groups based on the presence of histological chorioamnionitis (HC) with or without fetal involvement (HC-, n = 88; HC + F-, n = 25; HC + F+, n = 33) and between infants who developed bronchopulmonary dysplasia (BPD) or died (n = 57) and BPD-free survivors (n = 89). Multiple logistic regression was performed to investigate the association between HC and BPD.

RESULTS

Compared with HC- infants, HC + F+ infants had significantly greater FiO(2) requirement and prolonged time to extubation postsurfactant, not accounted for by differences in gestational age and birth weight. Infants with BPD/death had a strikingly similar pattern of increased FiO(2) requirement postsurfactant. Moreover, in infants who received surfactant, HC + F+ status was associated with increased risk for BPD (odds ratio [OR] = 3.40; 95% confidence interval [CI] = 1.02-11.3; P = .047) and for BPD/death (OR = 2.72; 95% CI = 1.00-7.42; P = .049).

CONCLUSIONS

An impaired surfactant response was observed in preterm infants with severe chorioamnionitis and may be involved in the association between chorioamnionitis, mechanical ventilation, and the development of BPD.

Reduced mortality and increased BPD with histological chorioamnionitis and leukocytosis in very-low-birth-weight infants

OBJECTIVE

To investigate the association between leukocytosis, mortality and bronchopulmonary dysplasia (BPD) in very-low-birth-weight infants (VLBW) born to mothers with histological chorioamnionitis.

STUDY DESIGN

A retrospective cohort study from a single level 3 neonatal intensive care unit. The study sample included infants born to mothers with histological chorioamnionitis (n=252). Total white blood cells (WBCs) after birth were measured. Leukocytosis was defined as a total WBC count >30 000 per mm(3) in the first 2 days of life. Outcomes investigated included BPD and death. Both unadjusted and multivariable analyses were carried out.

RESULT

After controlling for potential confounding variables, infants who developed a leukocytosis after birth had increased odds of BPD (4.6, 95% confidence interval (95% CI): 2.0 to 10.3), but decreased odds of death (0.3, 95% CI: 0.1 to 0.90).

CONCLUSION

In our population of VLBW infants born to mothers with histological chorioamnionitis, leukocytosis after birth is associated with a decrease in mortality but an increase in BPD.

Intrauterine inflammation, neonatal sepsis, and chronic lung disease: a 13-year hospital cohort study

OBJECTIVE To determine the impact of intrauterine inflammation of maternal (chorioamnionitis) and fetal (umbilical vasculitis) origin and neonatal sepsis on the development of neonatal chronic lung disease in preterm infants.

METHODS

This study was conducted at Royal Prince Alfred Hospital in Sydney, Australia. All infants born at <30 weeks' gestation, admitted to the NICU, and surviving to 36 weeks' corrected gestation during 1992-2004 were eligible. Infants with major congenital abnormalities and those without placental examination were excluded. Antenatal and perinatal data extracted from hospital databases were correlated with the independent, central neonatal database and diagnostic laboratory reports. Neonatal sepsis was categorized according to blood culture isolates into 3 groups: coagulase-negative staphylococci, other bacteria, and Candida species.

RESULTS

There were 798 eligible infants born during the study period, and 761 (95.4%) had placental examination. The mean gestational age was 27.4 +/- 1.5 weeks. Antenatal maternal steroids were given to 94.4%. Regression analysis showed that chorioamnionitis with umbilical vasculitis and increasing gestation were associated with reduced odds of chronic lung disease. Chorioamnionitis without umbilical vasculitis showed a trend to reduced odds of chronic lung disease. Birth weight at <3rd percentile and neonatal sepsis were associated with increased odds of chronic lung disease.

CONCLUSIONS

A fetal inflammatory response is protective for chronic lung disease. Neonatal sepsis is strongly associated with chronic lung disease, and the infecting organism is important. Coagulase-negative staphylococcal infection confers a risk for chronic lung disease similar to that of other bacteremias. Candidemia confers the greatest risk of chronic lung disease.

A multicenter study on the clinical outcome of chorioamnionitis in preterm infants

OBJECTIVE

The purpose of this study was to examine the effects of clinical maternal chorioamnionitis on morbidity and mortality rates among infants who are at < 33 weeks of gestation, adjusted for patient characteristics that included admission neonatal illness severity (Score for Neonatal Acute Physiology, version II; SNAP-II).

STUDY DESIGN

With multivariate logistic regression analysis, prospectively collected hospital outcomes from the Canadian Neonatal Network of singleton infants with birth gestational age of < 33 weeks and clinical chorioamnionitis were compared retrospectively with nonexposed infants.

RESULTS

Of 3094 infants, 477 infants (15.4%) who were exposed to clinical chorioamnionitis had significantly higher admission SNAP-II scores. Bivariate analysis revealed that the neonatal mortality rate was increased significantly in the chorioamnionitis group (10.6% vs 6.1%). Multivariate regression analysis with adjustment for illness severity indicated that chorioamnionitis was associated with an increased risk of early sepsis (odds ratio, 5.54; 95% confidence interval, 2.87-10.69) and severe intraventricular hemorrhage (odds ratio, 1.62; 95% confidence interval, 1.17-2.24) but not neonatal death.

CONCLUSION

Preterm infants who are exposed to clinical chorioamnionitis have an increased risk of early-onset sepsis and severe intraventricular hemorrhage.

Postnatal corticosteroids for bronchopulmonary dysplasia

Corticosteroids are used to improve lung function in infants who are progressing toward bronchopulmonary dysplasia. Corticosteroids facilitate extubation, but there is conflicting information about adverse effects on the developing brain. An approach to minimizing risk is to use low-dose, short-duration treatments in the highest risk ventilator-dependent patients. Questions remain about which corticosteroid is the safest and how to dose that corticosteroid.

Use of antibiotics for the treatment of preterm parturition and prevention of neonatal morbidity: a metaanalysis

OBJECTIVE

We conducted a metaanalysis to determine whether antibiotics prolong pregnancy and reduce neonatal morbidity in preterm premature rupture of membranes (PPROM) and preterm labor (PTL) at 34 weeks or less.

STUDY DESIGN

Randomized trials comparing antibiotic therapy with placebo in PPROM or PTL at a gestation of 34 weeks or less were retrieved. The primary outcome was time to delivery (latency). Infant outcomes included mortality, infection, neurological abnormality, respiratory disease, and neonatal stay.

RESULTS

Antibiotics were associated with prolongation of pregnancy in PPROM (P < .01) but not PTL. Clinically diagnosed neonatal infections were reduced in both groups; there was a trend toward reduced culture-positive sepsis in PPROM. Intraventricular hemorrhage (all grades) was reduced in PPROM. Other neonatal outcomes were unaffected by antenatal antibiotics.

CONCLUSION

Antibiotics prolong pregnancy and reduce neonatal morbidity in women with PPROM at a gestation of 34 weeks or less. In PTL at a gestation of 34 weeks or less, there is little evidence of benefit from administration of antibiotics.

Do cortisol concentrations predict short-term outcomes in extremely low birth weight infants?

OBJECTIVE

Relative adrenal insufficiency in extremely low birth weight infants may contribute to significant morbidity and death. Our objective was to evaluate the relationship between cortisol concentrations and short-term outcomes.

METHODS

Cortisol concentrations were obtained for 350 intubated, extremely low birth weight infants at postnatal age of 12 to 48 hours and at day 5 to 7, as part of a multicenter, randomized trial of hydrocortisone treatment for prophylaxis of relative adrenal insufficiency. Death and short-term morbidity were monitored prospectively. Cortisol levels at each time point were divided into quartiles. The incidence rates of outcomes were determined for each quartile and for infants with cortisol values of <10th percentile or >90th percentile. RESULTS. Median cortisol values were 16.0 microg/dL at baseline and 13.1 microg/dL on day 5 to 7 in the placebo group. Outcomes did not differ in each quartile between treatment and placebo groups. Low cortisol values at baseline or day 5 to 7 were not associated with increased morbidity or mortality rates and were not predictive of open-label hydrocortisone use. In fact, vasopressor use was lower for infants with lower cortisol values at baseline. Severe intraventricular hemorrhage was more frequent in infants with cortisol levels in the upper quartile at baseline, and values of >90th percentile were significantly associated with higher rates of death, severe intraventricular hemorrhage, periventricular leukomalacia, gastrointestinal perforation, and severe retinopathy of prematurity.

CONCLUSIONS

Low cortisol concentrations were not predictive of adverse short-term outcomes, but high cortisol concentrations were associated with severe intraventricular hemorrhage, and extremely elevated values were associated with morbidity and death. Low cortisol concentrations alone at these 2 time points did not identify the infants at highest risk for adverse outcomes. In contrast, high cortisol values were associated with increased morbidity and mortality rates.

Below median birth weight in appropriate-for-gestational-age preterm infants as a risk factor for bronchopulmonary dysplasia

AIMS

To assess the presence of chorioamnionitis and intrauterine growth as prenatal risk factors for broncho pulmonary dysplasia (BPD) in appropriate-for-gestational-age (AGA) infants of <28 weeks' gestation.

METHODS

Gender, race, birth weight, gestational age, histology of the placenta, diagnosis of BPD at 36 weeks' gestation, postnatal dexamethasone treatment, and death were recorded in 150 preterm infants born at <28 weeks' gestation, and admitted between 1996 and 2001.

RESULTS

In 122 AGA infants (mean gestational age: 26.18 weeks, mean birth weight: 837 g), BPD was associated with gestational age-related birth weights below the 50(th) centile. Intrauterine growth deceleration started between 25 and 26 weeks' gestation. Chorioamnionitis was not related to BPD.

CONCLUSIONS

AGA infants of 26-28 weeks' gestation with birth weights below the median showed an increased risk of developing BPD.

Hydrocortisone administration for the treatment of refractory hypotension in critically ill newborns

OBJECTIVE

The purpose of this observation was to evaluate the safety and efficacy of hydrocortisone (HC) for the treatment of refractory hypotension in term and preterm infants. A secondary purpose was to determine the utility of serum cortisol concentrations in predicting the response to treatment.

STUDY DESIGN

This is a retrospective observational study of 117 infants treated with a standardized HC protocol for refractory hypotension. Refractory hypotension was defined as a mean arterial pressure (MAP) less than the gestational age (GA) despite a total inotrope dose of 20 microg per kg per min. Baseline serum cortisol concentrations were determined prior to treatment with stress dose HC.

RESULT

Treatment with HC increased the MAP at 2, 6, 12 and 24 h after initiation, decreased the total inotrope dose at 6, 12 and 24 h, and was associated with resolution of oliguria. There was no correlation between the pretreatment baseline cortisol concentration and GA, birth weight or the response to treatment. The incidence of grades III to IV intraventricular hemorrhage, periventricular leukomalacia, bacterial or fungal sepsis and spontaneous intestinal perforation (SIP) after HC treatment was similar to institutional historic controls prior to institution of this standardized HC protocol.

CONCLUSION

HC treatment was associated with a rapid resolution of cardiovascular compromise. The incidence of significant side effects was similar to that in previously published reports, including a comparable incidence of SIP. On the basis of our results, measuring baseline serum cortisol concentration to guide the management of refractory hypotension is unwarranted.

Fetal cortisol response to intrauterine microbial colonisation identified by the polymerase chain reaction and fetal inflammation

OBJECTIVE

To determine the fetal cortisol response to intrauterine infection.

STUDY DESIGN

16s ribosomal RNA genes or the urease genes of Ureaplasma spp were identified by the polymerase chain reaction in intrauterine samples. Cord blood cortisol, interleukin 6 (IL6) and IL8 were measured in samples from 31 infants born at <32 weeks gestation.

RESULTS

13 infants (median gestation 30 weeks, birth weight 1350 g) had at least one positive intrauterine sample for microbial genes and 18 infants (31 weeks, 1320 g) did not. The cord blood cortisol concentration was significantly higher in fetuses exposed to intrauterine infection and significantly increased in fetuses/mothers presenting in preterm labour with intact membranes compared with infants delivered by elective prelabour caesarean section (p<0.05). The cord blood cortisol concentration was increased in the mothers with prelabour premature rupture of membranes but this was not significant compared with the caesarean section group. The cord blood cortisol concentration was significantly increased in the presence of chorioamnionitis or funisitis and was moderately correlated with cord blood IL6 (r = 0.64, p<0.01) and IL8 (r = 0.52, p<0.01).

CONCLUSIONS

In this study, cord blood cortisol was increased in the colonised group compared with non-colonised infants. It is unclear if infants born following prelabour premature rupture of the membranes mount an adequate anti-inflammatory response.

Cord blood KL-6, a specific lung injury marker, correlates with the subsequent development and severity of atypical bronchopulmonary dysplasia

BACKGROUND

A considerable number of preterm infants may have been exposed to inflammation in utero and may be born with an inflamed lung.

OBJECTIVES

To determine the impact of antenatal lung injury and inflammatory response on the pathogenesis of bronchopulmonary dysplasia (BPD) according to its clinical pattern, using KL-6 (as a lung injury marker) and C-reactive protein (CRP) (as a marker of inflammatory response).

METHODS

In this case-control study, a total of 74 infants (<32 weeks of gestation) including BPD with minimal early lung disease ('atypical'; 21 infants), BPD with significant early lung disease ('classic'; 29 infants) and the non-BPD (24 infants) groups underwent KL-6 and CRP in cord blood determinations.

RESULTS

The cord plasma KL-6 levels were significantly higher in the atypical and the total BPD groups than in the non-BPD group (median = 60.9 vs. 34.5 U/ml, p = 0.031; 43.5 vs. 34.5 U/ml, p = 0.02). However, the cord plasma CRP levels were not significantly different among the study groups. The cord plasma KL-6 levels in patients with atypical BPD were significantly higher in infants with moderate or severe BPD than in infants with mild BPD (median = 88.3 vs. 41.5 U/ml, p = 0.041) and were found to be significantly correlated with the duration of oxygen therapy (r = 0.502, p = 0.024).

CONCLUSIONS

The present study shows that cord plasma KL-6, a specific lung injury marker, is increased and objectively reflects disease severity in atypical BPD.

[Chorioamnionitis and lung damage in the extremely low birth weight infant]

Some experimental work suggests that exposure to intrauterine infection is associated, not only, with lung maturation and a reduced risk of respiratory distress syndrome, but also, with delayed alveolarization and increased risk of bronchopulmonary dysplasia.

AIM

To evaluate the association between histological chorioamnionitis and lung disease in extremely low birth weight preterm infants.

METHODS

A retrospective chart review of 63 less than 1000 g birthweight, appropriated for gestational age neonates, delivered at three tertiary medical centers in the north of Portugal, between 2001 and 2002. The association between histological chorioamnionitis and lung damage (respiratory distress syndrome and bronchopulmonary dysplasia) was evaluated through the calculation of crude and adjusted odds ratio.

RESULTS

There were 32 newborns from mothers with histological chorioamnionitis and 31 without the condition. The association between histological chorioamnionitis and respiratory distress syndrome was OR 0.23 (95% CI 0.01 - 2.51). The association between chorioamnionitis and bronchopulmonary dysplasia was OR 1.61 (95% CI 0.38 - 6.97). The association between histological chorioamnionitis and bronchopulmonary dysplasia when adjusted for gestational age, multiple birth and C-section revealed no statistical significance: OR 2.66 (95% CI 0.36 - 19.60) for chorio- amnionitis without funisitis or vasculitis and OR 1.68 (95% CI 0.25 - 11.18) for funisitis and/or vasculitis.

CONCLUSION

In this study we could not confirm a decreased risk of respiratory distress syndrome nor an increased risk of bronchopulmonary dysplasia in extremely low birth weight preterm neonates with histological chorioamnionitis

Growth and neurodevelopmental outcomes after early low-dose hydrocortisone treatment in extremely low birth weight infants

BACKGROUND

Low cortisol concentrations in premature infants have been correlated with increased severity of illness, hypotension, mortality, and development of bronchopulmonary dysplasia. A total of 360 mechanically ventilated infants with a birth weight of 500 to 999 g were enrolled in a randomized, multicenter trial of prophylaxis of early adrenal insufficiency to prevent bronchopulmonary dysplasia. Mortality and bronchopulmonary dysplasia were decreased in the hydrocortisone-treated patients exposed to chorioamnionitis. We now report outcomes at 18 to 22 months' corrected age.

PATIENTS AND METHODS

Surviving infants were evaluated with standardized neurologic examination and Bayley Scales of Infant Development-II. Neurodevelopmental impairment was defined as a Mental Developmental Index or Psychomotor Developmental Index of <70, cerebral palsy, blindness or deafness.

RESULTS

A total of 252 (87%) of 291 survivors were evaluated. Cerebral palsy was diagnosed in 13% of hydrocortisone-treated versus 14% of placebo-treated infants. Fewer hydrocortisone-treated infants had a Mental Development Index <70, and more of the hydrocortisone-treated infants showed evidence of awareness of object permanence. Incidence of neurodevelopmental impairment was not different (39% [hydrocortisone] vs 44% [placebo]). There were no differences in physical growth measures. Chorioamnionitis-exposed infants treated with hydrocortisone were shorter and weighed less than controls but had no evidence of neurodevelopmental impairment. Among infants not exposed to chorioamnionitis, hydrocortisone-treated patients were less likely to have a Mental Development Index of <70 or to be receiving glucocorticoids at follow-up.

CONCLUSIONS

Early, low-dose hydrocortisone treatment was not associated with increased cerebral palsy. Treated infants had indicators of improved developmental outcome. Together with the short-term benefit previously reported, these data support additional studies of hydrocortisone treatment of adrenal insufficiency in extremely premature infants.

Chorioamnionitis and fetal response in stillbirth

OBJECTIVE

The purpose of this study was to determine the incidence of chorioamnionitis and fetal inflammatory response in a stillborn cohort and the relationship of fetal response to spontaneous labor, unexplained antepartum death, and spontaneous preterm death.

STUDY DESIGN

In a 15-year hospital cohort study, placental histopathologic evidence, labor onset, gestation, and cause of death classification data were analyzed.

RESULTS

Of 459 stillbirths, 428 stillbirths were included. The incidence of chorioamnionitis was 36.9%, with higher rates evident in early and late gestation. A fetal inflammatory response was present in 13.3% and correlated with spontaneous labor and very early spontaneous preterm death. The absence of a fetal response was associated with unexplained antepartum death.

CONCLUSION

The increased incidence of chorioamnionitis at extremes of gestation in stillbirth is novel and has important implications. The impact of a fetal response is gestation dependent and its absence is associated with unexplained antepartum death.