"Miracle" extremely low birth weight neonates: examples of developmental plasticity

Risk Factors of Neonatal Acute Respiratory Distress Syndrome Based on the Montreux Definition in Neonates with Sepsis: A Retrospective Case-Control Study

OBJECTIVE

The aim of the study is to analyze the risk factors for neonatal acute respiratory distress syndrome (NARDS) development based on the Montreux definition among near- and full-term neonates with sepsis and received meropenem.

STUDY DESIGN

This was a single-center, case-control, retrospective trial from January 2019 to June 2020. Newborns of gestational ages (GAs) ≥35 weeks, diagnosed with sepsis and received meropenem were included. Patients who developed NARDS subsequently were defined as the study group (NARDS group), while the others without NARDS were enrolled in the control group (non-NARDS group).

RESULTS

Out of 213 eligible neonates, NARDS occurred in 52 (24.4%) cases. In univariate analysis, infants with NARDS had a lower GA and birth weight, but a higher rate of premature birth (p <0.05). The median onset times of sepsis were earlier among neonates with NARDS compared with those without NARDS (1 [1,1] vs. 6 [1,15] days, p <0.001). Neonates with NARDS were more likely to suffer from early-onset sepsis (EOS), persistent pulmonary hypertension of newborns, pulmonary hemorrhage, septic shock, and patent ductus arteriosus (p <0.05). During labor, women whose neonates experienced NARDS were more likely to have a cesarean delivery (67.3 vs. 46.6%, p = 0.009) and likely to receive at least one dose of corticosteroids (21.2 vs. 5.0%, p = 0.001). In multivariable analyses, factors remaining independently associated with NARDS were premature birth, cesarean delivery, EOS, and septic shock. Compared with conventional inflammatory markers for NARDS, procalcitonin (PCT) was correlated with septic neonates who developed NARDS (p = 0.012) but had a low diagnostic value (area under the curve [AUC] = 0.609). C-reactive protein, white blood cells, and PLT did not correlate with morbidity of NARDS (AUC <0.05 and p >0.05).

CONCLUSION

Premature birth, cesarean delivery, EOS, and septic shock were independently associated with NARDS among near- and full-term septic neonates. PCT showed limited predictive value for NARDS.

KEY POINTS

· NARDS is serious and sepsis is proved as a cause for it.. · But rare study suggests the risk factors of NARDS based on the Montreux definition.. · This study may first found the independent risk factors associated with NARDS in septic neonates..

Relationship between chorioamnionitis or funisitis and lung injury among preterm infants: meta-analysis involved 16 observational studies with 68,397 participants

BACKGROUND

Chorioamnionitis (CA) can cause multiple organ injuries in premature neonates, particularly to the lungs. Different opinions exist regarding the impact of intrauterine inflammation on neonatal respiratory distress syndrome (NRDS) and bronchopulmonary dysplasia (BPD). We aim to systematically review the relationship between CA or Funisitis (FV) and lung injury among preterm infants.

METHODS

We electronically searched PubMed, EMbase, the Cochrane library, CNKI, and CMB for cohort studies from their inception to March 15, 2023. Two reviewers independently screened literature, gathered data, and did NOS scale of included studies. The meta-analysis was performed using RevMan 5.3.

RESULTS

Sixteen observational studies including 68,397 patients were collected. Meta-analysis showed CA or FV increased the lung injury risk (OR = 1.43, 95%CI: 1.06-1.92). Except for histological chorioamnionitis (HCA) (OR = 0.72, 95%CI: 0.57-0.90), neither clinical chorioamnionitis (CCA) (OR = 1.86, 95%CI: 0.93-3.72) nor FV (OR = 1.23, 95%CI: 0.48-3.15) nor HCA with FV (OR = 1.85, 95%CI: 0.15-22.63) had statistical significance in NRDS incidence. As a result of stratification by grade of HCA, HCA (II) has a significant association with decreased incidence of NRDS (OR = 0.48, 95%CI: 0.35-0.65). In terms of BPD, there is a positive correlation between BPD and CA/FV (CA: OR = 3.18, 95%CI: 1.68-6.03; FV: OR = 6.36, 95%CI: 2.45-16.52). Among CA, HCA was positively associated with BPD (OR = 2.70, 95%CI: 2.38-3.07), whereas CCA was not associated with BPD (OR = 2.77, 95%CI: 0.68-11.21). HCA and moderate to severe BPD (OR = 25.38, 95%CI: 7.13-90.32) showed a positive correlation, while mild BPD (OR = 2.29, 95%CI: 0.99-5.31) did not.

CONCLUSION

Currently, evidence suggests that CA or FV increases the lung injury incidence in premature infants. For different types of CA and FV, HCA can increase the incidence of BPD while decreasing the incidence of NRDS. And this "protective effect" only applies to infants under 32 weeks of age. Regarding lung injury severity, only moderate to severe cases of BPD were positively correlated with CA.

Risk Factors and Age-Related Patterns of Asthma-Like Symptoms in Early Childhood

BACKGROUND

Episodes of asthma-like symptoms in young children are common, but little is known about risk factors and their patterns for the daily symptom burden.

OBJECTIVE

We investigated a variety of possible risk factors and their age-related impact on the number of asthma-like episodes during age 0 to 3 years.

METHODS

The study population included 700 children from the Copenhagen Prospective Studies on Asthma in Childhood2010 mother-child cohort followed prospectively from birth. Asthma-like symptoms were recorded until age 3 by daily diaries. Risk factors were analyzed by quasi-Poisson regressions, and interaction with age was explored.

RESULTS

Diary data were available in 662 children. Male sex, maternal asthma, low birth weight, maternal antibiotic use, high asthma exacerbation polygenic risk score, and high airway immune score were associated with a higher number of episodes in a multivariable analysis. Maternal asthma, preterm birth, caesarean section, and low birth weight showed an increasing impact with age, whereas sibling(s) at birth showed a decreased association with age. The remaining risk factors had a stable pattern during age 0 to 3 years. For every additional clinical risk factor (male sex, low birth weight, and maternal asthma) a child had, we found 34% more episodes (incidence rate ratio: 1.34, 95% confidence interval: 1.21-1.48; P < .001).

CONCLUSION

Using unique day-to-day diary recordings, we identified risk factors for the burden of asthma-like symptoms in the first 3 years of life and described their unique age-related patterns. This provides novel insight into the origin of asthma-like symptoms in early childhood that potentially pave a path for personalized prognostics and treatment.

Early Spontaneous Movements and Postural Patterns in Infants With Extremely Low Birth Weight

BACKGROUND

Extremely-low-birth-weight (ELBW) infants are at high risk of morbidity, mortality, and long-term neurodevelopmental disorders. Evaluating infants' early spontaneous movements and postural patterns could facilitate the early detection of neurological dysfunction. This study aimed to analyze the results of global-and detailed-General Movements Assessment (GMA) in ELBW infants at a corrected age of three to five months and to compare with normal-birth-weight (NBW) infants.

METHODS

Fifty-two ELBW infants (median birth weight = 915.5 g) and 50 NBW infants were included. All infants were assessed according to GMA using Motor Optimality Score for 3- to 5-Month-Old Infants-Revised score sheet (MOS-R). In addition, later diagnoses of ELBW infants with atypical development were presented.

RESULTS

Fidgety movements were observed in 36 (69.2%) of ELBW infants and all NBW infants. MOS-R scores were lower in the ELBW group (median = 24) compared with the NBW group (median = 26). The ELBW infants scored lower than NBW infants in all MOS-R subcategories. Twenty-three (44.2%) of ELBW infants were diagnosed as atypical in the later period, although all control infants had normal development.

CONCLUSIONS

The study indicated that ELBW might increase the risk of atypical development in infants. The MOS-R could help us to find the risk of atypical development in infants with ELBW.

[Association of different stages of histological chorioamnionitis with respiratory distress syndrome in preterm infants with a gestational age of < 32 weeks]

OBJECTIVE

To study the association of different stages of histological chorioamnionitis (HCA) with the incidence rate and severity of respiratory distress syndrome (RDS) in preterm infants.

METHODS

Related data were collected from the infants and their mothers who were treated in the Neonatal Intensive Care Unit of Qingdao Women and Children's Hospital, Qingdao University, from January 2018 to June 2020. According to the presence or absence of HCA and its stage, the infants were divided into four groups: control (n=109), early-stage HCA (n=126), middle-stage HCA (n=105), and late-stage HCA (n=36). The four groups were compared in terms of gestational age, birth weight, sex, maternal age, placental abruption, prenatal use of antibiotics, and incidence rate of RDS. The correlation between HCA stage and RDS severity was analyzed.

RESULTS

Compared with the control and late-stage HCA groups, the early-stage HCA group had a significantly lower incidence rate of placental abruption and a significantly higher rate of prenatal use of antibiotics (P < 0.05), and the early-stage HCA group had a significantly lower incidence rate of RDS than the control group (P < 0.05). The multivariate logistic regression analysis showed that early-, middle-, and late-stage HCA were protective factors against RDS (P < 0.05). The Spearman test showed that the severity of RDS in preterm infants was not correlated with the HCA stage (P > 0.05).

CONCLUSIONS

Early-, middle-, and late-stage HCA can reduce the incidence rate of RDS in preterm infants. HCA stage may not be correlated with RDS severity in preterm infants, which needs to be verified by further research.

Prenatal Risk Predicts Preschooler Executive Function: A Cascade Model

Little research has considered whether prenatal experience contributes to executive function (EF) development above and beyond postnatal experience. This study tests direct, mediated, and moderated associations between prenatal risk factors and preschool EF and IQ in a longitudinal sample of 1,292 children from the Family Life Project. A composite of prenatal risk factors (i.e., low birth weight, prematurity, maternal emotional problems, maternal prepregnancy obesity, and obstetric complications) significantly predicted EF and IQ at age 3, above quality of the postnatal environment. This relationship was indirect, mediated through infant general cognitive abilities. Quality of the postnatal home and child-care environments did not moderate the cascade model. These findings highlight the role of prenatal experience as a contributor to individual differences in cognitive development.

A Systematic Review of the Predictive Validity of Neurobehavioral Assessments During the Preterm Period

AIMS

For high-risk newborns, early assessment of neurobehavior that accurately predicts neurodevelopmental outcome is the first step towards determining early intervention needs. This study reviews systematically the validity of neurobehavioral assessments administered to premature newborns before term-equivalent age to predict long-term neurodevelopmental outcome.

METHODS

A systematic literature search of CINAHL, EMBASE, MEDLINE, PubMed, Web of Science, PsychInfo, Cochrane Library databases was conducted. PRISMA and COSMIN guidelines were followed.

RESULTS

Five assessments and 11 studies were identified: (a) Neonatal Behavioral Assessment Scale (NBAS); (b) Test of Infant Motor Performance (TIMP); (c) General Movements (GMs); (d) Neurobehavioral Assessment of the Preterm Infant (NAPI); (e) Neonatal Oral Motor Assessment Scale (NOMAS). Predictive validity estimates were variable. The GMs and TIMP showed the strongest associations with neurodevelopmental outcome. Threats to validity included small sample size, sample bias, limited reliability testing.

CONCLUSIONS

Five neurobehavioral measures have established predictive validity for the assessment of premature newborns while they reside in the NICU. Although the GMs and TIMP have the strongest evidence, further higher quality research is required. New methods of testing should be developed that provide accurate prediction and minimize the potential stress induced during developmental assessments.

The Montreux definition of neonatal ARDS: biological and clinical background behind the description of a new entity

Acute respiratory distress syndrome (ARDS) is undefined in neonates, despite the long-standing existing formal recognition of ARDS syndrome in later life. We describe the Neonatal ARDS Project: an international, collaborative, multicentre, and multidisciplinary project which aimed to produce an ARDS consensus definition for neonates that is applicable from the perinatal period. The definition was created through discussions between five expert members of the European Society for Paediatric and Neonatal Intensive Care; four experts of the European Society for Paediatric Research; two independent experts from the USA and two from Australia. This Position Paper provides the first consensus definition for neonatal ARDS (called the Montreux definition). We also provide expert consensus that mechanisms causing ARDS in adults and older children-namely complex surfactant dysfunction, lung tissue inflammation, loss of lung volume, increased shunt, and diffuse alveolar damage-are also present in several critical neonatal respiratory disorders.

FGR in the setting of preterm sterile intra-uterine milieu is associated with a decrease in RDS

OBJECTIVE

To determine if fetal growth restriction (FGR) in the setting of sterile intra-uterine milieu would be associated with a decrease in respiratory distress syndrome (RDS) of preterm-neonates.

METHODS

The relationship between FGR and neonatal RDS was examined in 92 singleton preterm-neonates (gestational age [GA]: 24.5-33.4 weeks) born to mothers with sterile intra-uterine milieu, which consisted of both sterile amniotic fluid (AF), and inflammation-free placenta. Sterile AF was defined in the absence of both infection and inflammation in AF. AF inflammation was defined in the presence of AF MMP-8 ≥23 ng/ml. FGR was defined in the presence of birth-weight (BW) below the 5th percentile for GA.

RESULTS

FGR was present in 32% and RDS was found in 46% of patients. RDS was less common (24% vs. 56%; P < 0.01) and umbilical arterial pH at birth ≤7.15 was more common (33% vs. 13%; P < 0.05) in preterm-neonates with FGR than in those without FGR. There is a stepwise increase in RDS with increasing BW (i.e., below the 5th percentile, the 5th ∼10th percentile, and above the 10th percentile for GA) (P < 0.01, linear by linear association). Logistic regression analysis demonstrated that FGR was a better independent predictor of a decrease in RDS (OR = 0.049, 95%CI 0.009-0.259, P < 0.0005) than advanced GA at delivery (OR = 0.584, 95%CI 0.423-0.806, P < 0.005) after adjusting for other confounding variables.

CONCLUSION

FGR in the setting of sterile intra-uterine milieu is associated with a decrease in RDS of preterm-neonates. This observation suggests that chronic intra-uterine hypoxic stress related to FGR may be beneficial to fetal lung maturation. Pediatr Pulmonol. 2016;51:812-819. © 2015 Wiley Periodicals, Inc.

Perinatal conditions related to growth restriction and inflammation are associated with an increased risk of bronchopulmonary dysplasia

AIM

Bronchopulmonary dysplasia (BPD) is a frequent chronic lung disease in preterm infants, and we aimed to identify factors associated with this condition in infants with respiratory distress syndrome (RDS).

METHODS

This case-control study, using national Swedish data, included 2255 preterm infants, born before 33 gestational weeks. The 667 BPD cases were oxygen dependent at 36 weeks' postmenstrual age, and the 1558 controls only had RDS. Comparisons included perinatal conditions and pharmacological treatments. Adjusted odds ratios with 95% confidence intervals were calculated in a conditional logistic regression model, with gestational age as the conditioning term.

RESULTS

An increased risk of BPD was associated with prelabour preterm rupture of membranes of more than 1 week (3.35, 2.16-5.19), small for gestational age (2.73, 2.11-3.55), low Apgar score (1.37, 1.05-1.81), patent ductus arteriosus (1.70, 1.33-2.18), persistent pulmonary hypertension (5.80, 3.21-10.50), pulmonary interstitial emphysema (2.78, 1.37-5.64), pneumothorax (2.95, 1.85-4.72), late onset infections (2.69, 1.82-3.98), intubation (1.56, 1.20-2.03), chest compressions (2.05, 1.15-3.66) and mechanical ventilation (2.16, 1.69-2.77), but not antenatal corticosteroids.

CONCLUSION

Growth restriction and inflammation increased the risk of BPD in preterm infants and prelabour preterm rupture of membranes, small for gestational age, low Apgar score or need for resuscitation should raise clinical suspicions.

Mild to Moderate, but Not Minimal or Severe, Acute Histologic Chorioamnionitis or Intra-Amniotic Inflammation Is Associated with a Decrease in Respiratory Distress Syndrome of Preterm Newborns without Fetal Growth Restriction

BACKGROUND

Acute histologic chorioamnionitis (acute-HCA) is known to be associated with a decreased risk of respiratory distress syndrome (RDS) in newborns. However, there is no information about whether the severity of acute-HCA or intra-amniotic inflammation (IAI) is associated with the development of RDS.

OBJECTIVES

To assess the relationship between the severity of acute-HCA or IAI and the development of RDS in preterm newborns due to preterm labor and intact membranes (PTL) or preterm premature rupture of membranes (preterm-PROM) without fetal growth restriction (FGR).

METHODS

The frequency of RDS was examined in 378 singleton preterm neonates (24.5-34 weeks' gestation) due to PTL or preterm-PROM without FGR. Patients were divided into 4 groups according to the severity of acute-HCA (i.e. total grade: minimal, 1; mild, 2; moderate, 3-4; severe, 5-6) or IAI (i.e. amniotic fluid MMP-8: minimal, 23-100 ng/ml; mild, 100-400 ng/ml; moderate, 400-800 ng/ml; severe, ≥800 ng/ml). Amniotic fluid MMP-8 was measured in 196 patients delivered within 7 days of amniocentesis.

RESULTS

Mild to moderate, but not minimal or severe, acute-HCA (minimal, 24%; mild, 13%; moderate, 19%; severe, 41%; preterm-reference group, 26%) or IAI (minimal, 24%; mild, 11%; moderate, 17%; severe, 25%; preterm reference group, 23%) was associated with a significant decrease in RDS as compared with the preterm reference group (each for p < 0.05 after the adjustment of gestational age at delivery, antenatal corticosteroid use, newborn gender, cesarean delivery and preterm-PROM as a cause of preterm birth).

CONCLUSIONS

Mild to moderate, but not minimal or severe, acute-HCA or IAI is associated with a significant decrease in RDS among preterm neonates due to PTL or preterm-PROM without FGR.

Prenatal inflammatory risk factors for development of bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a serious, chronic lung disease affecting preterm infants.

OBJECTIVE

To identify prenatal risk factors for BPD, focusing on inflammation.

METHODS

Observational cohort study including 106,339 preterm infants, live born before gestational week 37 + 0, from 1988 to 2009 in Sweden. A total of 2,115 infants were diagnosed with BPD, of which 1,393 were born extremely preterm, before gestational week 28 + 0. Information on risk factors was obtained from national health registers and included maternal chronic inflammatory diseases, pregnancy related diseases, and drugs related to treatment of inflammation or infection during pregnancy. Adjusted odds ratios (OR) were calculated in multivariable logistic regression models and are presented with 95% confidence intervals [95% CI].

RESULTS

Preeclampsia was the strongest risk factor for BPD [adjusted OR 2.04, 95% CI 1.83, 2.29]. For extremely preterm infants the adjusted OR was 1.33 [95% CI 1.08, 1.64]. Chorioamnionitis was associated with an increased risk of BPD, but only when including all infants in the analyses [OR 1.33, 95% CI 1.19, 1.48]. No apparent associations were found between maternal chronic inflammatory disease or use of anti-inflammatory drugs and the risk of BPD. Maternal diabetes mellitus, gestational diabetes and maternal use of antibiotics were associated with reduced risks of BPD.

CONCLUSION

Preeclampsia related disorders increased the risk and maternal diabetes mellitus and gestational diabetes reduced the risk for BPD. As angiogenic factors play a role in preeclampsia and diabetes our findings suggest that an impaired angiogenesis may contribute to BPD development.

Association of maternal hypertension and chorioamnionitis with preterm outcomes

OBJECTIVES

We compared the relative effect of hypertensive disorders of pregnancy and chorioamnionitis on adverse neonatal outcomes in very preterm neonates, and studied whether gestational age (GA) modulates these effects.

METHODS

A cohort of neonates 23 to 30 weeks' GA, born in 2008 to 2011 in 82 hospitals adhering to the Italian Neonatal Network, was analyzed. Infants born from mothers who had hypertensive disorders (N = 2096) were compared with those born after chorioamnionitis (N = 1510). Statistical analysis employed logistic models, adjusting for GA, hospital, and potential confounders.

RESULTS

Overall mortality was higher after hypertension than after chorioamnionitis (odds ratio [OR], 1.39; 95% confidence interval [CI], 1.08-1.80), but this relationship changed across GA weeks; the OR for hypertension was highest at low GA, whereas from 28 weeks' GA onward, mortality was higher for chorioamnionitis. For other outcomes, the relative risks were constant across GA; infants born after hypertension had an increased risk for bronchopulmonary dysplasia (OR, 2.20; 95% CI, 1.68-2.88) and severe retinopathy of prematurity (OR, 1.48; 95% CI, 1.02-2.15), whereas there was a lower risk for early-onset sepsis (OR, 0.25; 95% CI, 0.19-0.34), severe intraventricular hemorrhage (OR, 0.65; 95% CI, 0.48-0.88), periventricular leukomalacia (OR, 0.70; 95% CI, 0.48-1.01), and surgical necrotizing enterocolitis or gastrointestinal perforation (OR, 0.47; 95% CI, 0.31-0.72).

CONCLUSIONS

Mortality and other adverse outcomes in very preterm infants depend on antecedents of preterm birth. Hypertension and chorioamnionitis are associated with different patterns of outcomes; for mortality, the effect changes across GA weeks.

Preterm birth and childhood wheezing disorders: a systematic review and meta-analysis

BACKGROUND

Accumulating evidence implicates early life factors in the aetiology of non-communicable diseases, including asthma/wheezing disorders. We undertook a systematic review investigating risks of asthma/wheezing disorders in children born preterm, including the increasing numbers who, as a result of advances in neonatal care, now survive very preterm birth.

METHODS AND FINDINGS

Two reviewers independently searched seven online databases for contemporaneous (1 January 1995-23 September 2013) epidemiological studies investigating the association between preterm birth and asthma/wheezing disorders. Additional studies were identified through reference and citation searches, and contacting international experts. Quality appraisal was undertaken using the Effective Public Health Practice Project instrument. We pooled unadjusted and adjusted effect estimates using random-effects meta-analysis, investigated "dose-response" associations, and undertook subgroup, sensitivity, and meta-regression analyses to assess the robustness of associations. We identified 42 eligible studies from six continents. Twelve were excluded for population overlap, leaving 30 unique studies involving 1,543,639 children. Preterm birth was associated with an increased risk of wheezing disorders in unadjusted (13.7% versus 8.3%; odds ratio [OR] 1.71, 95% CI 1.57-1.87; 26 studies including 1,500,916 children) and adjusted analyses (OR 1.46, 95% CI 1.29-1.65; 17 studies including 874,710 children). The risk was particularly high among children born very preterm (<32 wk gestation; unadjusted: OR 3.00, 95% CI 2.61-3.44; adjusted: OR 2.81, 95% CI 2.55-3.12). Findings were most pronounced for studies with low risk of bias and were consistent across sensitivity analyses. The estimated population-attributable risk of preterm birth for childhood wheezing disorders was ≥3.1%. Key limitations related to the paucity of data from low- and middle-income countries, and risk of residual confounding.

CONCLUSIONS

There is compelling evidence that preterm birth-particularly very preterm birth-increases the risk of asthma. Given the projected global increases in children surviving preterm births, research now needs to focus on understanding underlying mechanisms, and then to translate these insights into the development of preventive interventions.

REVIEW REGISTRATION

PROSPERO CRD42013004965.

Chorioamnionitis and subsequent lung function in preterm infants

OBJECTIVE

To explore the relationship between prematurity, gender and chorioamnionitis as determinants of early life lung function in premature infants.

METHODS

Placenta and membranes were collected from preterm deliveries (<37 weeks gestational age) and evaluated for histological chorioamnionitis (HCA). Patients were followed and lung function was performed in the first year of life by Raised Volume-Rapid Thoracic Compression Technique.

RESULTS

Ninety-five infants (43 males) born prematurely (median gestational age 34.2 weeks) were recruited. HCA was detected in 66 (69%) of the placentas, and of these 55(58%) were scored HCA Grade 1, and 11(12%) HCA Grade 2. Infants exposed to HCA Grade 1 and Grade 2, when compared to those not exposed, presented significantly lower gestational ages, higher prevalence of RDS, clinical early-onset sepsis, and the use of supplemental oxygen more than 28 days. Infants exposed to HCA also had significantly lower maximal flows. There was a significant negative trend for z-scores of lung function in relation to levels of HCA; infants had lower maximal expiratory flows with increasing level of HCA. (p = 0.012 for FEF50, p = 0.014 for FEF25-75 and p = 0.32 for FEV0.5). Two-way ANOVA adjusted for length and gestational age indicated a significant interaction between sex and HCA in determining expiratory flows (p<0.01 for FEF50, FEF25-75 and p<0.05 for FEV0.5). Post-hoc comparisons revealed that female preterm infants exposed to HCA Grade 1 and Grade 2 had significant lower lung function than those not exposed, and this effect was not observed among males.

CONCLUSIONS

Our findings show a sex-specific negative effect of prenatal inflammation on lung function of female preterm infants. This study confirms and expands knowledge upon the known association between chorioamnionitis and early life chronic lung disease.

Intra-amniotic IL-1β induces fetal inflammation in rhesus monkeys and alters the regulatory T cell/IL-17 balance

Very low birth weight preterm newborns are susceptible to the development of debilitating inflammatory diseases, many of which are associated with chorioamnionitis. To define the effects of chorioamnionitis on the fetal immune system, IL-1β was administered intra-amniotically at ~80% gestation in rhesus monkeys. IL-1β caused histological chorioamnionitis, as well as lung inflammation (infiltration of neutrophils or monocytes in the fetal airways). There were large increases in multiple proinflammatory cytokine mRNAs in the lungs at 24 h postadministration, which remained elevated relative to controls at 72 h. Intra-amniotic IL-1β also induced the sustained expression of the surfactant proteins in the lungs. Importantly, IL-1β significantly altered the balance between inflammatory and regulatory T cells. Twenty-four hours after IL-1β injection, the frequency of CD3(+)CD4(+)FOXP3(+) T cells was decreased in lymphoid organs. In contrast, IL-17A-producing cells (CD3(+)CD4(+), CD3(+)CD4(-), and CD3(-)CD4(-) subsets) were increased in lymphoid organs. The frequency of IFN-γ-expressing cells did not change. In this model of a single exposure to an inflammatory trigger, CD3(+)CD4(+)FOXP3(+) cells rebounded quickly, and their frequency was increased at 72 h compared with controls. IL-17 expression was also transient. Interestingly, the T cell profile alteration was confined to the lymphoid organs and not to circulating fetal T cells. Together, these results suggest that the chorioamnionitis-induced IL-1/IL-17 axis is involved in the severe inflammation that can develop in preterm newborns. Boosting regulatory T cells and/or controlling IL-17 may provide a means to ameliorate these abnormalities.