Perinatal systemic inflammatory response syndrome and retinopathy of prematurity

An iTRAQ-Based Quantitative Proteomic Analysis of Plasma Proteins in Preterm Newborns With Retinopathy of Prematurity

Purpose

Retinopathy of prematurity (ROP) is a vision-threatening complication of a premature birth, in which the etiology still remains unclear. Importantly, the molecular processes that govern these effects can be investigated in a perturbed plasma proteome composition. Thus, plasma proteomics may add new insights into a better understanding of the pathogenesis of this disease.

Methods

The cord and peripheral blood of neonates (≤30 weeks gestational age) was drawn at birth and at the 36th postmenstrual week (PMA), respectively. Blood samples were retrospectively subdivided into ROP(+) and ROP(-) groups, according to the development of ROP.

Results

The quantitative analysis of plasma proteome at both time points revealed 30 protein abundance changes between ROP(+) and ROP(-) groups. After standardization to gestational age, children who developed ROP were characterized by an increased C3 complement component and fibrinogen level at both analyzed time points.

Conclusions

Higher levels of the complement C3 component and fibrinogen, present in the cord blood and persistent to 36 PMA, may indicate a chronic low-grade systemic inflammation and hypercoagulable state that may play a role in the development of ROP.

Prenatal complications are associated with the postnatal airway host response and microbiota in intubated preterm infants

PURPOSE

To prospectively examine the relationship between prenatal events, postnatal airway host response and microbiota, and clinical outcomes.

MATERIALS AND METHODS

Tracheal aspirates collected at seven days of age from 71 mechanically ventilated infants (median gestational age (GA), 25 weeks [range 23-28]) were simultaneously processed for a 12-plex protein assay and bacterial identification by 16S rRNA sequencing. Phenotypes were determined by unsupervised clustering of the protein analytes. Subject characteristics, microbial communities and clinical factors and outcomes were compared across the phenotype groups.

RESULTS

Three clusters were identified: 1 (high protein levels), 2 (high proinflammatory proteins and low anti-inflammatory proteins), and 3 (low protein levels), respectively. Antenatal hemorrhage was most common in cluster 1, while chorioamnionitis characterized cluster 2 and preeclampsia was most prevalent in cluster 3, which was characterized by a predominance of Staphylococcus and relative absence of Ureaplasma. There were higher rates of adverse clinical outcomes in cluster 1.

CONCLUSIONS

Airway protein profiles in seven days old mechanically ventilated preterm infants are associated with important antenatal events and unique airway microbial communities. These relationships may reveal new mechanisms by which antenatal events impact the course and outcomes of preterm infants.

Interleukin-17: The Role for Pathological Angiogenesis in Ocular Neovascular Diseases

Ocular neovascular diseases are featured by abnormal angiogenesis in the eye, and they seriously threaten the human visual health. These diseases include proliferative diabetic retinopathy (PDR), age-related macular degeneration (AMD), retinopathy of prematurity (ROP), and retinal vein occlusion (RVO). In fact, ocular neovascular diseases represent the leading causes of vision impairment and blindness worldwide. Ocular neovascularization, the process of pathological vessel formation in eye, underlies ocular neovascular diseases. Cytokines have important regulatory roles in neovascularization through immunological networks. Interleukin (IL)-17, the signature cytokine produced by T helper 17 (Th17) cells, has proven to be involved in ocular neovascularization. However, roles of IL-17 in ocular neovascular diseases still remain controversial. This review provides an overview of the functional roles of IL-17 in ocular neovascular diseases from basic research to clinical evidence by focusing on PDR, AMD, ROP, and RVO. The possible roles of IL-17 in neovascularization are achieved through a regulatory network of cytoskeleton remodeling, vascular endothelial growth factor (VEGF), VEGF-related cytokines, and complement components. Current applications as well as potential therapies targeting IL-17 with genome editing systems are also outlined and discussed. Targeting IL-17 might be a promising therapeutic strategy against ocular neovascular diseases.

Impact of different stages of intrauterine inflammation on outcome of preterm neonates: Gestational age-dependent and -independent effect

Objective

To investigate the impact of different stages of intrauterine inflammation (IUI) on neonatal outcomes, before and after adjusting for gestational age (GA) and other perinatal confounders.

Methods

This was an observational, prospective, single-center cohort study including all eligible neonates with GA < 35 weeks and/or birth weight ≤ 1500 g born at a 3^rd level Neonatal Intensive Care Unit between 2011 and 2014. Pathological patterns of placenta, membranes and cord were classified according to Redline’s criteria. Multivariable linear and logistic regression models were applied, either including or not GA among the covariates.

Results

Of the 807 enrolled neonates, 134 (16.6%) had signs of IUI: among these, 54.5% showed just histological chorioamnionitis (HCA), 25.4% had HCA + funisitis (FUN) stage 1, and 20.1% had HCA + FUN stage 2–3. At univariate analysis, HCA increased the risk for retinopathy of prematurity (ROP) and bronchopulmonary dysplasia, while FUN (any stage) had a deleterious impact on all outcomes investigated. After adjustment for covariates not including GA, HCA was a risk factor only for ROP (OR = 2.8, CI: 1–7.8), while FUN (any stage) was still associated with increased ORs for all outcomes (p <0.01). Upon inclusion of GA in the regression model, the results differed remarkably. HCA was associated with lower risk for mechanical ventilation (OR = 0.3, CI: 0.1–0.7) and need for surfactant (OR = 0.5, CI: 0.2–0.9), while FUN (any stage) worsened clinical conditions at birth (p <0.05), increased the risk for early-onset sepsis (p <0.01), and increased the length of mechanical ventilation (FUN stage 2–3 only, RC = 6.5 days, CI: 2–11). No other outcome was affected.

Conclusions

IUI, especially FUN, negatively impact most neonatal morbidities, but its effect is partially reverted adjusting for GA. Considered that GA is an intermediate variable interposed between prenatal causes of prematurity and outcomes, the appropriateness of adjusting for GA may be questionable.

The genetics of retinopathy of prematurity: a model for neovascular retinal disease

TOPIC

Retinopathy of prematurity (ROP) is a proliferative retinal vascular disease in premature infants, and is a major cause of childhood blindness worldwide. In addition to known clinical risk factors such as low birth weight and gestational age, there is a growing body of evidence supporting a genetic basis for ROP.

CLINICAL RELEVANCE

While comorbidities and environmental factors have been identified as contributing to ROP outcomes in premature infants, most notably gestational age and oxygen, some infants progress to severe disease despite absence of these clinical risk factors. The contribution of genetic factors may explain these differences and allow better detection and treatment of infants at risk for severe ROP.

METHODS

To comprehensively review genetic factors that potentially contribute to the development and severity of ROP, we conducted a literature search focusing on the genetic basis for ROP. Terms related to other heritable retinal vascular diseases like "familial exudative vitreoretinopathy", as well as to genes implicated in animal models of ROP, were also used to capture research in diseases with similar pathogenesis to ROP in humans with known genetic components.

RESULTS

Contributions across several genetic domains are described including vascular endothelial growth factor, the Wnt signaling pathway, insulin-like growth factor 1, inflammatory mediators, and brain-derived neurotrophic factor.

CONCLUSIONS

Most candidate gene studies of ROP have limitations such as inability to replicate results, conflicting results from various studies, small sample size, and differences in clinical characterization. Additional difficulty arises in separating the contribution of genetic factors like Wnt signaling to ROP and prematurity. Although studies have implicated involvement of multiple signaling pathways in ROP, the genetics of ROP have not been clearly elucidated. Next-generation sequencing and genome-wide association studies have potential to expand future understanding of underlying genetic risk factors and pathophysiology of ROP.

Antenatal IL-1-dependent inflammation persists postnatally and causes retinal and sub-retinal vasculopathy in progeny

Antenatal inflammation as seen with chorioamnionitis is harmful to foetal/neonatal organ development including to eyes. Although the major pro-inflammatory cytokine IL-1β participates in retinopathy induced by hyperoxia (a predisposing factor to retinopathy of prematurity), the specific role of antenatal IL-1β associated with preterm birth (PTB) in retinal vasculopathy (independent of hyperoxia) is unknown. Using a murine model of PTB induced with IL-1β injection in utero, we studied consequent retinal and choroidal vascular development; in this process we evaluated the efficacy of IL-1R antagonists. Eyes of foetuses exposed only to IL-1β displayed high levels of pro-inflammatory genes, and a persistent postnatal infiltration of inflammatory cells. This prolonged inflammatory response was associated with: (1) a marked delay in retinal vessel growth; (2) long-lasting thinning of the choroid; and (3) long-term morphological and functional alterations of the retina. Antenatal administration of IL-1R antagonists - 101.10 (a modulator of IL-1R) more so than Kineret (competitive IL-1R antagonist) - prevented all deleterious effects of inflammation. This study unveils a key role for IL-1β, a major mediator of chorioamnionitis, in causing sustained ocular inflammation and perinatal vascular eye injury, and highlights the efficacy of antenatal 101.10 to suppress deleterious inflammation.

Chronic Placental Inflammation as a Risk Factor of Severe Retinopathy of Prematurity

Background

Chronic placental inflammation (CPI) has been implicated in the pathogenesis of diseases in premature infants, whereas retinopathy of prematurity (ROP) is a major complication primarily affecting preterm and very low-birth-weight (VLBW) infants. This study aims to investigate the association between CPI and ROP in VLBW infants.

Methods

We performed a retrospective review of clinical records of VLBW infants born between 2013 and 2016. Placental pathology findings including CPI cases were analyzed using logistic regression to study infants’ morbidities and other clinical characteristics.

Results

A total of 402 infants with a mean (standard deviation) gestational age of 28.5 (2.8) weeks and birth weight of 1,027.2 (304.4) g were included. The incidence of ROP was 24.1%. CPI was found in 90 infants (22.4%), among which 28.9% (26 of 90) developed ROP, and 21.1% (19 of 90) underwent laser photocoagulation. Lower gestational age, lower birth weight, longer duration of oxygen supply, and presence of CPI were associated with the development of ROP. After adjustment for gestational age, birth weight, sex, duration of oxygen supply, and other overlapping placental pathology, CPI was associated with the odds for type 1 ROP that required laser photocoagulation (adjusted odds ratio, 2.739; 95% confidence interval, 1.112 to 6.749; p = .029).

Conclusions

CPI was associated with severe ROP requiring treatment with laser photocoagulation in VLBW infants.

Aqueous cytokine levels associated with severity of type 1 retinopathy of prematurity and treatment response to ranibizumab

PURPOSE

To determine the aqueous humor levels of cytokines in eyes with type 1 retinopathy of prematurity (ROP) before primary intravitreal injection of ranibizumab (IVR).

METHODS

Forty-nine infants with type 1 ROP (56 eyes of 28 infants in the threshold ROP group and 42 eyes of 21 infants in the type 1 pre-threshold ROP group) received primary IVR and 49 aqueous humor samples were obtained preoperatively. Aqueous humor samples from 15 infants (15 eyes) undergoing congenital cataract surgery were used as controls. The concentrations of 27 cytokines were measured by a multiplex bead assay. Infants with persistent, recurrent, or progressive ROP after IVR were retreated.

RESULTS

The preoperative aqueous levels of 16 cytokines were significantly different among type 1 pre-threshold, threshold ROP, and control groups (P < 0.05). The concentrations of vascular endothelial growth factor (VEGF) (P < 0.001), interferon-γ (P < 0.001), interleukin (IL)-10 (P < 0.001), and IL-12 (P < 0.001) were the highest in the threshold ROP group, less in the type 1 pre-threshold ROP group, and the lowest in the control group. Retreatment was given to 55% of infants with ROP within a 48-week follow-up period after primary IVR. Higher VEGF (hazard ratio [HR] = 1.001, P = 0.001) and macrophage inflammatory protein-1β (HR = 1.085, P = 0.022) levels were independently correlated with ROP retreatment.

CONCLUSIONS

Higher aqueous levels of VEGF and inflammatory cytokines were associated with more severe type 1 ROP and ROP retreatment after primary IVR.

Retinopathy of prematurity: a review of risk factors and their clinical significance

Retinopathy of prematurity (ROP) is a retinal vasoproliferative disease that affects premature infants. Despite improvements in neonatal care and management guidelines, ROP remains a leading cause of childhood blindness worldwide. Current screening guidelines are primarily based on two risk factors: birth weight and gestational age; however, many investigators have suggested other risk factors, including maternal factors, prenatal and perinatal factors, demographics, medical interventions, comorbidities of prematurity, nutrition, and genetic factors. We review the existing literature addressing various possible ROP risk factors. Although there have been contradictory reports, and the risk may vary between different populations, understanding ROP risk factors is essential to develop predictive models, to gain insights into pathophysiology of retinal vascular diseases and diseases of prematurity, and to determine future directions in management of and research in ROP.

Increased postnatal concentrations of pro-inflammatory cytokines are associated with reduced IGF-I levels and retinopathy of prematurity

OBJECTIVE

Retinopathy of prematurity (ROP) is a multifactorial disease linked to low insulin-like growth factor (IGF)-I levels and perhaps to postnatal inflammation. Here, we investigated the longitudinal postnatal serum concentrations of pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α in relation to IGF-I levels and ROP.

DESIGN

The study cohort included 52 infants born before 31 gestational weeks. The infants were screened for ROP and classified as non-ROP (n=33), non-proliferative ROP (stages 1 and 2; n=10), or proliferative ROP (stage 3, all treated for ROP; n=9). Blood samples were collected at birth, 24h after birth, and then weekly until at least 36weeks postmenstrual age (PMA) (i.e., up to 13weeks after birth). Circulating levels of IL-6 and TNF-α were evaluated in relation to circulating IGF-I levels and ROP.

RESULTS

IL-6 levels negatively correlated with IGF-I levels between 5 and 8weeks after birth, (p<0.01 to p<0.05). At birth, the IL-6 and TNF-α levels were similar independent of later ROP. Twenty-four hours after birth, both IL-6 and TNF-α levels had increased in infants later treated for ROP (p<0.05). Postnatal, infants treated for ROP had higher IL-6 levels than infants without ROP.

CONCLUSIONS

The pro-inflammatory response is associated with low IGF-I levels and the development of ROP.

Systemic Inflammation-Associated Proteins and Retinopathy of Prematurity in Infants Born Before the 28th Week of Gestation

Purpose

To assess the association between systemic levels of inflammation-associated proteins and severe retinopathy of prematurity (ROP) in extremely preterm infants.

Methods

We collected whole blood on filter paper on postnatal days 1, 7, 14, 21, and 28 from 1205 infants born before the 28th week of gestation, and measured the concentrations of 27 inflammation-associated, angiogenic, and neurotrophic proteins. We calculated odds ratios with 95% confidence intervals for the association between top quartile concentrations of each protein and prethreshold ROP.

Results

During the first three weeks after birth, high concentrations of VEGF-R1, myeloperoxidase (MPO), IL-8, intercellular adhesion molecule (ICAM)-1, matrix metalloproteinase 9, erythropoietin, TNF-α, and basic fibroblast growth factor were associated with an increased risk for prethreshold ROP. On day 28, high levels of serum amyloid A, MPO, IL-6, TNF-α, TNF-R1/-R2, IL-8, and ICAM-1 were associated with an increased risk. Top quartile concentrations of the proinflammatory cytokines TNF-α and IL-6 were associated with increased risks of ROP when levels of neuroprotective proteins and growth factors, including BDNF, insulin-like growth factor 1, IGFBP-1, VEGFR-1 and -2, ANG-1 and PlGF, were not in the top quartile. In contrast, high concentrations of NT-4 and BDNF appeared protective only in infants without elevated inflammatory mediators.

Conclusions

Systemic inflammation during the first postnatal month was associated with an increased risk of prethreshold ROP. Elevated concentrations of growth factors, angiogenic proteins, and neurotrophins appeared to modulate this risk, and were capable of reducing the risk even in the absence of systemic inflammation.

Abnormal Complement Activation and Inflammation in the Pathogenesis of Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a neurovascular complication in preterm babies, leading to severe visual impairment, but the underlying mechanisms are yet unclear. The present study aimed at unraveling the molecular mechanisms underlying the pathogenesis of ROP. A comprehensive screening of candidate genes in preterms with ROP (n = 189) and no-ROP (n = 167) was undertaken to identify variants conferring disease susceptibility. Allele and genotype frequencies, linkage disequilibrium and haplotypes were analyzed to identify the ROP-associated variants. Variants in CFH (p = 2.94 × 10⁻⁷), CFB (p = 1.71 × 10⁻⁵), FBLN5 (p = 9.2 × 10⁻⁴), CETP (p = 2.99 × 10⁻⁵), and CXCR4 (p = 1.32 × 10⁻⁸) genes exhibited significant associations with ROP. Further, a quantitative assessment of 27 candidate proteins and cytokines in the vitreous and tear samples of babies with severe ROP (n = 30) and congenital cataract (n = 30) was undertaken by multiplex bead arrays and further validated by western blotting and zymography. Significant elevation and activation of MMP9 (p = 0.038), CFH (p = 2.24 × 10⁻⁵), C3 (p = 0.05), C4 (p = 0.001), IL-1ra (p = 0.0019), vascular endothelial growth factor (VEGF) (p = 0.0027), and G-CSF (p = 0.0099) proteins were observed in the vitreous of ROP babies suggesting an increased inflammation under hypoxic condition. Along with inflammatory markers, activated macrophage/microglia were also detected in the vitreous of ROP babies that secreted complement component C3, VEGF, IL-1ra, and MMP-9 under hypoxic stress in a cell culture model. Increased expression of the inflammatory markers like the IL-1ra (p = 0.014), MMP2 (p = 0.0085), and MMP-9 (p = 0.03) in the tears of babies at different stages of ROP further demonstrated their potential role in disease progression. Based on these findings, we conclude that increased complement activation in the retina/vitreous in turn activated microglia leading to increased inflammation. A quantitative assessment of inflammatory markers in tears could help in early prediction of ROP progression and facilitate effective management of the disease, thereby preventing visual impairment.

Chorioamnionitis, IL-17A, and fetal origins of neurologic disease

The Centers for Disease Control and Prevention estimate that 1 in 323 infants have cerebral palsy. Highly correlated to intrauterine infection and inflammation, the incidence of cerebral palsy has remained constant over the last few decades despite significant advances in neonatal intensive care including improved ventilator techniques, surfactant therapy, maternal steroid administration, and use of intrapartum empiric antimicrobials. Recent advances in our understanding of immune responses to infection and inflammation have identified the cytokine IL-17A as a crucial component of early proinflammatory mediators that cause brain injury associated with neurologic impairment. Remarkably, maternal inflammatory responses to in utero inflammation and infection can also lead to potentially debilitating neurologic conditions in the offspring, which often become clinically apparent during childhood and/or early adulthood. This review details the role of IL-17A in fetal and maternal proinflammatory responses that lead to fetal brain injury and neurologic sequelae, including cerebral palsy. Recent findings regarding the role of maternal inflammatory responses in the development of childhood and adult neurologic conditions, such as autism, schizophrenia, and multiple sclerosis, will also be highlighted.

Ischemic Retinopathies: Oxidative Stress and Inflammation

Ischemic retinopathies (IRs), such as retinopathy of prematurity (ROP), diabetic retinopathy (DR), and (in many cases) age-related macular degeneration (AMD), are ocular disorders characterized by an initial phase of microvascular changes that results in ischemia, followed by a second phase of abnormal neovascularization that may culminate into retinal detachment and blindness. IRs are complex retinal conditions in which several factors play a key role during the development of the different pathological stages of the disease. Increasing evidence reveals that oxidative stress and inflammatory processes are important contributors to the pathogenesis of IRs. Despite the beneficial effects of the photocoagulation and anti-VEGF therapy during neovascularization phase, the need to identify novel targets to prevent initial phases of these ocular pathologies is still needed. In this review, we provide an update on the involvement of oxidative stress and inflammation in the progression of IRs and address some therapeutic interventions by using antioxidants and anti-inflammatory agents.

The prognostic value of lymphocyte-to-monocyte ratio in retinopathy of prematurity

AIM

To evaluate the associations between development of retinopathy of prematurity (ROP) and serum lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR).

METHODS

A retrospective cohort study was performed, involving infants who were screened for ROP from January 2015 to December 2015. Preterm newborns of ≤32 gestational weeks with ROP were enrolled as the observation group, and non-ROP infants were enrolled as the control group, whose complete blood cell were measured within the first 24h of life. The levels of NLR, LMR and PLR were determined in all groups. The data obtained were analyzed using univariate and multivariate logistic regression analysis.

RESULTS

In this study, 40 cases of ROP were enrolled and 40 cases of non-ROP as controls. The LMR levels were significantly higher (P<0.001) in ROP group (3.96±1.16) compared to non-ROP group (2.85±0.79). The NLR levels were significantly lower (P=0.035) in ROP group {median [interquartile range (IQR)], 0.88 (0.67-1.46)} compared to non-ROP group [median (IQR), 1.20 (0.85-1.89)]. The median PLR values were 61.99 (IQR, 50.23-75.98) in ROP group and 69.24 (IQR, 55.52-88.12) in non-ROP group (P=0.104). Logistic regression analysis suggested that LMR was an independent risk factor for ROP (OR: 0.275; 95% CI: 0.134-0.564; P=0.001).

CONCLUSION

The findings demonstrate that higher LMR is independently and significantly associated with the development of ROP, and the LMR may be invoked as a predictive tool for identifying risk for ROP.

Foxp3+ Tregs are recruited to the retina to repair pathological angiogenesis

Neovascular retinopathies are major causes of vision loss; yet treatments to prevent the condition are inadequate. The role of regulatory T cells in neovascular retinopathy is unknown. Here we show that in retinopathy regulatory T cells are transiently increased in lymphoid organs and the retina, but decline when neovascularization is established. The decline is prevented following regulatory T cells expansion with an IL-2/anti-IL-2 mAb complex or the adoptive transfer of regulatory T cells. Further, both approaches reduce vasculopathy (vaso-obliteration, neovascularization, vascular leakage) and alter the activation of Tmem119⁺ retinal microglia. Our in vitro studies complement these findings, showing that retinal microglia co-cultured with regulatory T cells exhibit a reduction in co-stimulatory molecules and pro-inflammatory mediators that is attenuated by CTLA-4 blockade. Collectively, we demonstrate that regulatory T cells are recruited to the retina and, when expanded in number, repair the vasculature. Manipulation of regulatory T cell numbers is a previously unrecognized, and promising avenue for therapies to prevent blinding neovascular retinopathies.

The local immune responses in the eye are attenuated to preserve sight. Surprisingly, Deliyanti et al. show that regulatory T cells (Tregs) take an active role in protecting the eye from neovascularization in oxygen-induced retinopathy, and that interventions that augment the retinal Treg numbers reduce neovascular retinopathy in mice.

Pathophysiology, screening and treatment of ROP: A multi-disciplinary perspective

The population of infants at risk for retinopathy of prematurity (ROP) varies by world region; in countries with well developed neonatal intensive care services, the highest risk infants are those born at less than 28 weeks gestational age (GA) and less than 1 kg at birth, while, in regions where many aspects of neonatal intensive and ophthalmological care are not routinely available, more mature infants up to 2000 g at birth and 37 weeks GA are also at risk for severe ROP. Treatment options for both groups of patients include standard retinal laser photocoagulation or, more recently, intravitreal anti-VEGF drugs. In addition to detection and treatment of ROP, this review highlights new opportunities created by telemedicine, where screening and diagnosis of ROP in remote locations can be undertaken by non-ophthalmologists using digital fundus cameras. The ophthalmological care of the ROP infant is undertaken in the wider context of neonatal care and general wellbeing of the infant. Because of this context, this review takes a multi-disciplinary perspective with contributions from retinal vascular biologists, pediatric ophthalmologists, an epidemiologist and a neonatologist. This review highlights the latest insights regarding cellular and molecular mechanisms in the formation of the retinal vasculature in the human infant, pathogenesis of ROP, detection and treatment of severe ROP, the risks and benefits of anti-VEGF therapy, the identification of new therapies over the horizon, and the optimal neonatal care regimen for best ROP outcomes, and the benefits and pitfalls of telemedicine in the remote screening and diagnosis of ROP, all of which have the potential to improve ROP outcomes.

Association of Maternal Preeclampsia With Infant Risk of Premature Birth and Retinopathy of Prematurity

Importance

Studies report conflicting associations between preeclampsia and retinopathy of prematurity (ROP). This study provides explanations for the discrepancies to clarify the relationship between preeclampsia and ROP.

Objective

To evaluate the association of maternal preeclampsia and risk of ROP among infants in an unrestricted birth cohort and a restricted subcohort of preterm, very low birth weight (P-VLBW) infants.

Design, Setting, and Participants

A retrospective review of 290 992 live births within the Intermountain Healthcare System in Utah from January 1, 2001, through December 31, 2010, was performed. Generalized estimating equations for logistic regressions with covariate adjustment were applied to relate ROP to preeclampsia among the full cohort and in a subcohort of P-VLBW infants born at younger than 31 weeks' gestation and weighing less than 1500 g.

Main Outcomes and Measures

The occurrence of ROP was related to maternal preeclampsia in the full cohort and in a subcohort of P-VLBW infants.

Results

In the full cohort, 51% of the infants were male and the mean (SD) gestational age was 38.38 (1.87) weeks. In the P-VLBW cohort, 55% were male and the mean (SD) gestational age was 26.87 (2.40) weeks. In the full cohort, preeclampsia was associated with an increased risk of all ROP (adjusted odds ratio [aOR], 2.46; 95% CI, 2.17-2.79; P < .001), severe ROP (aOR, 5.21; 95% CI, 3.44-7.91; P < .001), infant death (aOR, 1.66; 95% CI, 1.16-2.38; P = .006), and giving birth to a P-VLBW infant (aOR, 7.74; 95% CI, 6.92-8.67; P < .001). In the P-VLBW subcohort, preeclampsia was inversely associated with the development of all ROP (aOR, 0.79; 95% CI, 0.68-0.92; P = .003), severe ROP (aOR, 0.62; 95% CI, 0.36-1.06; P = .08), and infant death (aOR, 0.19; 95% CI, 0.11-0.32; P < .001).

Conclusions and Relevance

Preeclampsia was associated with an increased risk of developing ROP among an unrestricted cohort but with a reduced risk of ROP among a restricted subcohort of P-VLBW infants. Although the conflicting associations in the full and P-VLBW cohorts may reflect true differences, the association of a reduced risk of ROP among the P-VLBW subcohort also may reflect biases from restricting the cohort to prematurity, because prematurity is an outcome of preeclampsia.

Retinopathy of prematurity: inflammation, choroidal degeneration, and novel promising therapeutic strategies

Retinopathy of prematurity (ROP) is an important cause of childhood blindness globally, and the incidence is rising. The disease is characterized by initial arrested retinal vascularization followed by neovascularization and ensuing retinal detachment causing permanent visual loss. Although neovascularization can be effectively treated via retinal laser ablation, it is unknown which children are at risk of entering this vision-threatening phase of the disease. Laser ablation may itself induce visual field deficits, and there is therefore a need to identify targets for novel and less destructive treatments of ROP. Inflammation is considered a key contributor to the pathogenesis of ROP. A large proportion of preterm infants with ROP will have residual visual loss linked to loss of photoreceptor (PR) and the integrity of the retinal pigment epithelium (RPE) in the macular region. Recent studies using animal models of ROP suggest that choroidal degeneration may be associated with a loss of integrity of the outer retina, a phenomenon so far largely undescribed in ROP pathogenesis. In this review, we highlight inflammatory and neuron-derived factors related to ROP progression, as well, potential targets for new treatment strategies. We also introduce choroidal degeneration as a significant cause of residual visual loss following ROP. We propose that ROP should no longer be considered an inner retinal vasculopathy only, but also a disease of choroidal degeneration affecting both retinal pigment epithelium and photoreceptor integrity.

Antecedents and correlates of blood concentrations of neurotrophic growth factors in very preterm newborns

AIM

To identify the antecedents and very early correlates of low concentrations of neurotrophic growth factors in the blood of extremely preterm newborns during the first postnatal month.

METHODS

Using an immunobead assay, we measured the concentrations of neurotrophin 4 (NT4), brain-derived neurotrophic factor (BDNF), and basic fibroblast growth factor (bFGF) in blood spots collected on postnatal days 1 (N=1062), 7 (N=1087), 14 (N=989), 21 (N=940) and 28 (N=880) from infants born before the 28th week of gestation. We then sought the correlates of measurements in the top and bottom quartiles for gestational age and day the specimen was collected.

RESULTS

The concentrations of 2 neurotrophic proteins, NT4 and BDNF, were low among children delivered for medical (maternal or fetal) indications, and among those who were growth restricted. Children who had top quartile concentrations of NT4, BDNF, and bFGF tended to have elevated concentrations of inflammation-related proteins that day. This pattern persisted for much of the first postnatal month.

CONCLUSIONS

Delivery for medical indications and fetal growth restriction are associated with a relative paucity of NT4 and BDNF concentrations during the first 24 h after very preterm birth. Elevated blood concentrations of NT4, BDNF, and bFGF tended to co-occur with indicators of systemic inflammation on the same day.

Simultaneous Fluorescein Angiography and Spectral Domain Optical Coherence Tomography Correlate Retinal Thickness Changes to Vascular Abnormalities in an In Vivo Mouse Model of Retinopathy of Prematurity

Background

Retinopathy of prematurity (ROP) is a condition of abnormal retinal vascular development (RVD) in premature infants. Fluorescein angiography (FA) has depicted phases (early, mid, late, and mature) of RVD in oxygen-induced retinopathy (OIR) mice. We sought to establish the relationship between retinal structural and vascular changes using simultaneous FA and spectral domain optical coherence tomography (SD-OCT).

Method

63 mice were exposed to 77% oxygen at postnatal day 7 (P7) for 5 days, while 63 mice remained in room air (RA). Total retinal thickness (TRT), inner retinal thickness (IRT), and outer retinal thickness (ORT) were calculated at early (P19), mid (P24), late (P32), and mature (P47) phases of RVD.

Results

TRT was reduced in OIR (162.66 ± 17.75 μm, n = 13) compared to RA mice at P19 (197.57 ± 3.49 μm, n = 14), P24, P32, and P49 (P < 0.0001). ORT was similar in RA and OIR mice at all ages (P > 0.05). IRT was reduced in OIR (71.60 ± 17.14 μm) compared to RA (103.07 ± 3.47 μm) mice at P19 and all ages (P < 0.0001).

Conclusion

We have shown the spatial and temporal relationship between retinal structure and vascular development in OIR. Significant inner retinal thinning in OIR mice persisted despite revascularization of the capillary network; further studies will elucidate its functional implications in ROP.

Advances in understanding and management of retinopathy of prematurity

The understanding, diagnosis, and treatment of retinopathy of prematurity have changed in the 70 years since the original description of retrolental fibroplasia associated with high oxygenation. It is now recognized that retinopathy of prematurity differs in appearance worldwide and as ever smaller and younger premature infants survive. New methods are being evaluated to image the retina, diagnose severe retinopathy of prematurity, and determine windows of time for treatment to save eyes and improve visual and neural outcomes. New treatments to promote physiologic retinal vascular development, vascular repair, and inhibit vasoproliferation by regulating proteins involved in vascular endothelial growth factor, insulin-like growth factor, or erythropoietin signaling. Reducing excessive oxidative/nitrosative stress and understanding progenitor cells and neurovascular and glial vascular interactions are being studied.

Metabolic Effects of Inflammation on Vitamin A and Carotenoids in Humans and Animal Models

The association between inflammation and vitamin A (VA) metabolism and status assessment has been documented in multiple studies with animals and humans. The relation between inflammation and carotenoid status is less clear. Nonetheless, it is well known that carotenoids are associated with certain health benefits. Understanding these relations is key to improving health outcomes and mortality risk in infants and young children. Hyporetinolemia, i.e., low serum retinol concentrations, occurs during inflammation, and this can lead to the misdiagnosis of VA deficiency. On the other hand, inflammation causes impaired VA absorption and urinary losses that can precipitate VA deficiency in at-risk groups of children. Many epidemiologic studies have suggested that high dietary carotenoid intake and elevated plasma concentrations are correlated with a decreased risk of several chronic diseases; however, large-scale carotenoid supplementation trials have been unable to confirm the health benefits and in some cases resulted in controversial results. However, it has been documented that dietary carotenoids and retinoids play important roles in innate and acquired immunity and in the body's response to inflammation. Although animal models have been useful in investigating retinoid effects on developmental immunity, it is more challenging to tease out the effects of carotenoids because of differences in the absorption, kinetics, and metabolism between humans and animal models. The current understanding of the relations between inflammation and retinoid and carotenoid metabolism and status are the topics of this review.

The Importance of Human Milk for Immunity in Preterm Infants

The immune system of preterm infants is immature, placing them at increased risk for serious immune-related complications. Human milk provides a variety of immune protective and immune maturation factors that are beneficial to the preterm infant's poorly developed immune system. The most studied immune components in human milk include antimicrobial proteins, maternal leukocytes, immunoglobulins, cytokines and chemokines, oligosaccharides, gangliosides, nucleotides, and long-chain polyunsaturated fatty acids. There is growing evidence that these components contribute to the lower incidence of immune-related conditions in the preterm infant. Therefore, provision of these components in human milk, donor milk, or formula may provide immunologic benefits.

Characteristic clinical features associated with aggressive posterior retinopathy of prematurity

PurposeTo identify the risk factors for, and clinical features and treatment outcomes of aggressive posterior retinopathy of prematurity (APROP) in Korean infants.MethodsAmong 770 premature infants who underwent screening, 105 infants (198 eyes, 13.63%) received treatment for ROP. A total of 24 infants (48 eyes, 3.12%) developed APROP while 81 infants (150 eyes, 10.52%) developed non-APROP treatment-requiring type. The medical records of ROP-treated infants were reviewed retrospectively. The associated systemic and maternal risk factors were analyzed and anatomical outcomes were compared according to the severity of ROP and treatment modalities.ResultsThe mean gestational age and birth weight at birth in the APROP group were significantly lower than those in the non-APROP group (P=0.019, P<0.001, respectively). Infants who were born small for their GA developed APROP more frequently than non-APROP patients (P<0.001). Chorioamnionitis-positive infants also showed higher incidence rate of APROP (APROP vs non-APROP; P<0.001 and zone I APROP vs posterior zone II APROP; P=0.036, respectively). Infants with APROP required heavier laser treatment with a higher retreatment rate compared to infants with non-APROP. Favorable anatomical outcomes were achieved in 95.3% from treatment-requiring non-APROP group, 85.7% from zone I APROP and 84.6% from posterior zone II APROP group.ConclusionIntrauterine growth restriction and chorioamnionitis were associated with development of APROP. These findings suggest that perinatal maternal environment inhibiting normal retinal vascular growth in utero may contribute to increasing the risk of APROP in premature infants.

Retinopathy of prematurity: Revisiting incidence and risk factors from Oman compared to other countries

Purpose:

The purpose of this study is to determine the incidence of retinopathy of prematurity (ROP) and the maternal/neonatal risk factors at a tertiary care hospital in Oman, compared to other countries.

Patients and Methods:

A retrospective analysis of premature neonates born with gestational age (GA) 24–32 weeks at Sultan Qaboos University Hospital, Oman, from January 2007 to December 2010. Maternal and neonatal in-hospital course was retrieved. The incidence of ROP was reported. Risk factors analyses were performed using univariate and multivariate statistics.

Results:

A total of 171 neonates (57% males, 43% females) were included for analysis. The incidence of ROP (any stage) was 69/171 (40.4%). Infants with ROP had significantly lower GA (27.7±2 weeks) compared to non-ROP group (30.2±1.7 weeks), P < 0.001),P < 0.001) and significantly lower birth weight (BW) (948 ± 242 g in ROP group vs. 1348 ± 283 g in non-ROP group;P < 0.001). Other significant risk factors associated with ROP were: small for GA, respiratory distress syndrome, requirement for ventilation, duration of ventilation or oxygen therapy, bronchopulmonary dysplasia, hyperglycemia, late onset sepsis (clinical or proven), necrotizing enterocolitis, patent ductus arteriosus, seizures, and number of blood transfusions. There was no significant difference in maternal characteristics between the ROP and non-ROP groups except that mothers of infants with ROP were found to be significantly younger. Logistic regression analysis revealed early GA, low BW, duration of Oxygen therapy, and late-onset clinical or proven sepsis as independent risk factors.

Conclusion:

ROP is still commonly encountered in neonatal practice in Oman and other countries. Early GA, low BW, and prolonged oxygen therapy continue to be the main risk factors associated with the occurrence of ROP in our setting. In addition, an important preventable risk factor identified in our cohort includes clinical or proven late-onset sepsis.

Review of the mechanisms and therapeutic avenues for retinal and choroidal vascular dysfunctions in retinopathy of prematurity

Retinopathy of prematurity (ROP) is a multifactorial disease and the main cause of visual impairment and blindness in premature neonates. The inner retina has been considered the primary region affected in ROP, but choroidal vascular degeneration and progressive outer retinal dysfunctions have also been observed. This review focuses on observations regarding neurovascular dysfunctions in both the inner and outer immature retina, the mechanisms and the neuronal-derived factors implicated in the development of ROP, as well potential therapeutic avenues for this disorder.

CONCLUSION

Alterations in the neurovascular integrity of the inner and outer retina contribute to the development of ROP.

Choroidal Involution Is Associated with a Progressive Degeneration of the Outer Retinal Function in a Model of Retinopathy of Prematurity: Early Role for IL-1β

Retinopathy of prematurity (ROP), the most common cause of blindness in premature infants, has long been associated with inner retinal alterations. However, recent studies reveal outer retinal dysfunctions in patients formerly afflicted with ROP. We have recently demonstrated that choroidal involution occurs early in retinopathy. Herein, we investigated the mechanisms underlying the choroidal involution and its long-term impact on retinal function. An oxygen-induced retinopathy (OIR) model was used. In vitro and ex vivo assays were applied to evaluate cytotoxic effects of IL-1β on choroidal endothelium. Electroretinogram was used to evaluate visual function. We found that proinflammatory IL-1β was markedly increased in retinal pigment epithelium (RPE)/choroid and positively correlated with choroidal degeneration in the early stages of retinopathy. IL-1β was found to be cytotoxic to choroid in vitro, ex vivo, and in vivo. Long-term effects on choroidal involution included a hypoxic outer neuroretina, associated with a progressive loss of RPE and photoreceptors, and visual deterioration. Early inhibition of IL-1β receptor preserved choroid, decreased subretinal hypoxia, and prevented RPE/photoreceptor death, resulting in life-long improved visual function in IL-1 receptor antagonist-treated OIR animals. Together, these findings suggest a critical role for IL-1β-induced choroidal degeneration in outer retinal dysfunction. Neonatal therapy using IL-1 receptor antagonist preserves choroid and prevents protracted outer neuroretinal anomalies in OIR, suggesting IL-1β as a potential therapeutic target in ROP.

FUNCTIONAL OUTCOMES OF YOUNG INFANTS WITH AND WITHOUT MACULAR EDEMA

PURPOSE

The authors relate posterior segment microanatomy from perinatal spectral domain optical coherence tomography to visual acuity, brain abnormalities, and neurodevelopment.

METHODS

Thirteen infants (11 preterm and 2 term birth), imaged in the nursery with portable spectral domain optical coherence tomography, had visual acuity and sensorimotor testing at age 9 months to 15 months (grating acuity) or 4 years to 5 years (optotype), and medical records reviewed for brain magnetic resonance imaging reports and Bayley scales testing at age 18 months to 24 months.

RESULTS

Eight children with age-appropriate macular microanatomy without edema on perinatal spectral domain optical coherence tomography had optimal (≥ 20/40) or within normal limits (grating acuity) visual acuity. Five children with perinatal macular edema had suboptimal visual acuity (in 9/10 eyes) and sensorimotor deficits, magnetic resonance imaging abnormalities, or poor neurodevelopment. Macular edema persisted in 1 infant through 9-month corrected age.

CONCLUSION

Maturation of the visual system and evolution of retinal anomalies can be monitored with posterior segment spectral domain optical coherence tomography. Retinal microanatomy observed in infancy might relate to subsequent vision and other central nervous system events, but additional studies are needed to determine the range of normal microanatomy in infants and how this relates to vision and neurodevelopment.

Inhibition of the Nuclear Receptor RORγ and Interleukin-17A Suppresses Neovascular Retinopathy: Involvement of Immunocompetent Microglia

OBJECTIVE

Although inhibitors of vascular endothelial growth factor (VEGF) provide benefit for the management of neovascular retinopathies, their use is limited to end-stage disease and some eyes are resistant. We hypothesized that retinoic acid-related orphan nuclear receptor γ (RORγ) and its downstream effector, interleukin (IL)-17A, upregulate VEGF and hence are important treatment targets for neovascular retinopathies.

APPROACH AND RESULTS

Utilizing a model of oxygen-induced retinopathy, confocal microscopy and flow cytometry, we identified that retinal immunocompetent cells, microglia, express IL-17A. This was confirmed in primary cultures of rat retinal microglia, where hypoxia increased IL-17A protein as well as IL-17A, RORγ, and tumor necrosis factor-α mRNA, which were reduced by the RORγ inhibitor, digoxin, and the RORα/RORγ inverse agonist, SR1001. By contrast, retinal macroglial Müller cells and ganglion cells, key sources of VEGF in oxygen-induced retinopathy, did not produce IL-17A when exposed to hypoxia and IL-1β. However, they expressed IL-17 receptors, and in response to IL-17A, secreted VEGF. This suggested that RORγ and IL-17A inhibition might attenuate neovascular retinopathy. Indeed, digoxin and SR1001 reduced retinal vaso-obliteration, neovascularization, and vascular leakage as well as VEGF and VEGF-related placental growth factor. Digoxin and SR1001 reduced microglial-derived IL-17A and Müller cell and ganglion cell damage. The importance of IL-17A in oxygen-induced retinopathy was confirmed by IL-17A neutralization reducing vasculopathy, VEGF, placental growth factor, tumor necrosis factor-α, microglial density and Müller cell, and ganglion cell injury.

CONCLUSIONS

Our findings indicate that an RORγ/IL-17A axis influences VEGF production and neovascular retinopathy by mechanisms involving neuroglia. Inhibition of RORγ and IL-17A may have potential for the improved treatment of neovascular retinopathies.

Clinical chorioamnionitis at term V: umbilical cord plasma cytokine profile in the context of a systemic maternal inflammatory response

OBJECTIVE

Microbial invasion of the fetus due to intra-amniotic infection can lead to a systemic inflammatory response characterized by elevated concentrations of cytokines in the umbilical cord plasma/serum. Clinical chorioamnionitis represents the maternal syndrome often associated with intra-amniotic infection, although other causes of this syndrome have been recently described. The objective of this study was to characterize the umbilical cord plasma cytokine profile in neonates born to mothers with clinical chorioamnionitis at term, according to the presence or absence of bacteria and/or intra-amniotic inflammation.

MATERIALS AND METHODS

A cross-sectional study was conducted, including patients with clinical chorioamnionitis at term (n=38; cases) and those with spontaneous term labor without clinical chorioamnionitis (n=77; controls). Women with clinical chorioamnionitis were classified according to the results of amniotic fluid culture, broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) and amniotic fluid interleukin (IL)-6 concentration into three groups: 1) no intra-amniotic inflammation; 2) intra-amniotic inflammation without detectable microorganisms; or 3) microbial-associated intra-amniotic inflammation. A fetal inflammatory response syndrome (FIRS) was defined as an umbilical cord plasma IL-6 concentration >11 pg/mL. The umbilical cord plasma concentrations of 29 cytokines were determined with sensitive and specific V-PLEX immunoassays. Nonparametric statistical methods were used for analysis, adjusting for a false discovery rate of 5%.

RESULTS

1) Neonates born to mothers with clinical chorioamnionitis at term (considered in toto) had significantly higher median umbilical cord plasma concentrations of IL-6, IL-12p70, IL-16, IL-13, IL-4, IL-10 and IL-8, but significantly lower interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF)-α concentrations than neonates born to mothers with spontaneous term labor without clinical chorioamnionitis; 2) neonates born to mothers with clinical chorioamnionitis at term but without intra-amniotic inflammation had higher concentrations of IL-6, IL-12p70, IL-13, IL-4, IL-5, and IL-8, but lower IFN-γ, than neonates not exposed to clinical chorioamnionitis, suggesting that maternal fever in the absence of intra-amniotic inflammation leads to a change in the fetal cytokine network; 3) there were significant, positive correlations between maternal and umbilical cord plasma IL-6 and IL-8 concentrations (IL-6: Spearman correlation=0.53; P<0.001; IL-8: Spearman correlation=0.42; P<0.001), consistent with placental transfer of cytokines; 4) an elevated fetal plasma IL-6 (>11 pg/mL), the diagnostic criterion for FIRS, was present in 21% of cases (8/38), and all these neonates were born to mothers with proven intra-amniotic infection; and 5) FIRS was associated with a high concentration of umbilical cord plasma IL-8, IL-10 and monocyte chemoattractant protein (MCP)-1.

CONCLUSIONS

Neonates born to mothers with clinical chorioamnionitis at term had higher concentrations of umbilical cord plasma cytokines than those born to mothers without clinical chorioamnionitis. Even neonates exposed to clinical chorioamnionitis but not to intra-amniotic inflammation had elevated concentrations of multiple cytokines, suggesting that intrapartum fever alters the fetal immune response.

Genomics in the neonatal nursery: Focus on ROP

Retinopathy of prematurity (ROP) is a complex disease that is influenced by both genetic and environmental factors. Several small studies have found genetic variants in EPAS1, VEGF, SOD, and members of the WNT family in association with ROP. Design in genetic studies is challenging because of changing recommendations for the management of prematurity and ROP, the fact ROP is rare, and that availability of resources for managing premature infants can vary throughout the world. In addition, there is a shortage of ophthalmologists with the ability to diagnose and characterize severe ROP. Careful determination of the degree of prematurity is important when evaluating genetic studies. Controlling for significant epidemiologic factors and multiple comparisons is also important to consider when evaluating genetic studies. One large candidate gene study controlled for degree of prematurity, significant epidemiologic factors, and multiple comparisons and found variants within the intron of BDNF associated with severe ROP. Future studies using unbiased techniques to assess genetic risk are important as are in-depth study of BDNF through deep sequencing and associated mechanistic studies using appropriate experimental models.

Serum neutrophil-to-lymphocyte ratio in retinopathy of prematurity

PURPOSE

To evaluate the relationship between serum neutrophil-to-lymphocyte ratio (NLR) and development of retinopathy of prematurity (ROP).

METHODS

Infants with a gestational age of ≤32 week were screened for ROP. Complete blood cell, high-sensitivity C-reactive protein, and interleukin 6 levels of subjects were measured within the first 24 hours of life. The NLR was calculated by dividing neutrophil count by lymphocyte count. The association between other risk factors and the development of ROP were analyzed using univariate analysis and multivariate logistic regression analysis.

RESULTS

A total of 100 infants were included: 80 with ROP and 20 without ROP. The NLR values differed significantly between the ROP group (median, 0.67; interquartile range, 0.38-1.09) and non-ROP group (median, 0.32; interquartile range, 0.22-0.79; P = 0.02). The lymphocyte count in the ROP group (4.01 ± 1.89) compared to that of the non-ROP group (5.69 ± 2.16) was significantly lower (P = 0.001). In multivariate analysis, lymphocyte count remained an independent predictor of ROP (OR = 0.599; 95% CI, 0.430-0.836; P = 0.003).

CONCLUSIONS

The NLR seems not to be an independent predictor of development of ROP. Lymphocyte count is inversely associated with ROP.

Predictors for the development of referral-warranted retinopathy of prematurity in the telemedicine approaches to evaluating acute-phase retinopathy of prematurity (e-ROP) study

IMPORTANCE

Detection of treatment-requiring retinopathy of prematurity (ROP) involves serial eye examinations. An ROP prediction model using predictive factors could identify high-risk infants and reduce required eye examinations.

OBJECTIVE

To determine predictive factors for the development of referral-warranted (RW) ROP.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter observational cohort study included secondary analysis of data from the Telemedicine Approaches to Evaluating Acute-Phase Retinopathy of Prematurity Study. Infants included in the study had a birth weight (BW) of less than 1251 g.

EXPOSURES

Serial ROP examinations of premature infants who had 2 or more ROP examinations.

MAIN OUTCOMES AND MEASURES

Incidence of RW-ROP (defined as the presence of plus disease, zone I ROP, or ROP stage 3 or greater in either eye) and associations with predictive factors.

RESULTS

Among 979 infants without RW-ROP at first study-related eye examination (median postmenstrual age, 33 weeks; range, 29-40 weeks) who underwent at least 2 eye examinations, 149 (15.2%) developed RW-ROP. In a multivariate model, significant predictors for RW-ROP were male sex (odds ratio [OR], 1.80; 95% CI, 1.13-2.86 vs female), nonblack race (OR, 2.76; 95% CI, 1.50-5.08 for white vs black race and OR, 4.81; 95% CI, 2.19-10.6 for other vs black race), low BW (OR, 5.16; 95% CI, 1.12-7.20 for ≤500 g vs >1100 g), younger gestational age (OR, 9.79; 95% CI, 3.49-27.5 for ≤24 weeks vs ≥28 weeks), number of quadrants with preplus disease (OR, 7.12; 95% CI, 2.53-20.1 for 1-2 quadrants and OR, 18.4; 95% CI, 4.28-79.4 for 3-4 quadrants vs no preplus disease), stage 2 ROP (OR, 4.13; 95% CI, 2.13-8.00 vs no ROP), the presence of retinal hemorrhage (OR, 4.36; 95% CI, 1.57-12.1 vs absence), the need for respiratory support (OR, 4.99; 95% CI, 1.89-13.2 for the need for controlled mechanical ventilator; OR, 11.0; 95% CI, 2.26-53.8 for the need for high-frequency oscillatory ventilation vs no respiratory support), and slow weight gain (OR, 2.44; 95% CI, 1.22-4.89 for weight gain ≤12 g/d vs >18 g/d). These characteristics predicted the development of RW-ROP significantly better than BW and gestational age (area under receiver operating characteristic curve, 0.88 vs 0.78; P < .001).

CONCLUSIONS AND RELEVANCE

When controlling for very low BW and prematurity, the presence of preplus disease, stage 2 ROP, retinal hemorrhage, and the need for ventilation at time of first study-related eye examination were strong independent predictors for RW-ROP. These predictors may help identify infants in need of timely eye examinations.

Proteomic profiling of the retinas in a neonatal rat model of oxygen-induced retinopathy with a reproducible ion-current-based MS1 approach

Investigation of the retina proteome during hypoxia-induced retinal neovascularization is valuable for understanding pathogenesis of retinopathy of prematurity (ROP). Here we employed a reproducible ion-current-based MS1 quantification approach (ICB) to explore the retinal proteomic changes in early stage of ROP in a rat model of oxygen-induced retinopathy (OIR). Retina proteins, which are rich in membrane proteins, were efficiently extracted by a detergent-cocktail and subjected to precipitation/on-pellet-digestion, followed by nano-LC-MS analysis on a 75-cm column with a 7-h gradient. The high reproducibility of sample preparation and chromatography separation enabled excellent peak alignment and contributed to the superior performance of ICB over parallel label-free approaches. In this study, sum-of-intensity with rejection was incorporated to determine the protein ratios. In total, 1325 unique protein groups were quantified from rat retinas (n = 4/group) with at least two distinct peptides at a protein FDR of 1%. Thirty-two significantly altered proteins were observed with confidence, and the elevated glial fibrillary acidic protein and decreased crystalline proteins in OIR retinas agree well with previous studies. Selected key alterations were further validated by Western blot analysis. Interestingly, Rab21/RhoA/ROCK2/moesin signaling pathway was found to be involved in retinal neovascularization of OIR. Moreover, highly elevated annexin A3, a potential angiogenic mediator, was observed in OIR retinas and may serve as a potential therapeutic target. In conclusion, reproducible ICB profiling enabled reliable discovery of many altered mediators and pathways in OIR retinas, thereby providing new insights into molecular mechanisms involved in pathogenesis of ROP.

Constitutively high-level expression of TGFβ isoforms in cord blood and its relationship to perinatal findings

BACKGROUND

The clinical significance of TGFβ isoforms in cord blood is not well understood.

METHODS

We obtained cord blood samples from 37 term infants and 85 preterm infants who were born in several clinical settings. The serum levels of 3 TGFβ isoforms and of the other 17 cytokines in cord blood were investigated using cytometric bead array technology.

RESULTS

Very high levels of TGFβ1 and TGFβ2 isoforms compared to the level of other cytokines were found; mean levels were 44,180 and 1871pg/mL, respectively. The levels of all 3 isoforms of TGFβ were significantly correlated with birth weight, and the levels of TGFβ1 and TGFβ3 were correlated with gestational age. The levels of TGFβ1 and β2 isoforms were strongly correlated with each other, but not with levels of other cytokines. The levels of TGFβ1 and TGFβ2 were significantly higher in male infants and significantly lower in infants with fetal growth restriction. The prevalence of chronic lung disease was related to a low level of TGFβ1, and that of patent ductus arteriosus was related to a high level of TGFβ1 in preterm infants.

CONCLUSIONS

TGFβ1 and TGFβ2 appeared to play a significant role in physiological and pathological conditions in the fetus. TGFβ isoform levels appear to be regulated independently of those of other cytokines and do not appear to be influenced by inflammation in the fetal period. The role of TGFβ3 in cord blood and the postnatal chronological changes of the TGFβ isoforms should be investigated in the future.

Role of macular xanthophylls in prevention of common neovascular retinopathies: retinopathy of prematurity and diabetic retinopathy

Retinopathy of prematurity (ROP) and diabetic retinopathy (DR) are important causes of blindness among children and working-age adults, respectively. The development of both diseases involves retinal microvascular degeneration, vessel loss and consequent hypoxic and inflammatory pathologic retinal neovascularization. Mechanistic studies have shown that oxidative stress and subsequent derangement of cell signaling are important factors in disease progression. In eye and vision research, role of the dietary xanthophyll carotenoids, lutein and zeaxanthin, has been more extensively studied in adult onset macular degeneration than these other retinopathies. These carotenoids also may decrease severity of ROP in preterm infants and of DR in working-age adults. A randomized controlled clinical trial of carotenoid supplementation in preterm infants indicated that lutein has functional effects in the neonatal eye and is anti-inflammatory. Three multicenter clinical trials all showed a trend of decreased ROP severity in the lutein supplemented group. Prospective studies on patients with non-proliferative DR indicate serum levels of lutein and zeaxanthin are significantly lower in these patients compared to normal subjects. The present review describes recent advances in lutein and zeaxanthin modulation of oxidative stress and inflammation related to ROP and DR and discusses potential roles of lutein/zeaxanthin in preventing or lessening the risks of disease initiation or progression.

Antecedents and correlates of visual field deficits in children born extremely preterm

AIM

We sought to identify the antecedents and correlates of visual field deficits (VFDs) at age 2 years among infants born before the 28th week of gestation.

METHODS

The visual fields of 1023 infants were assessed by confrontation at age 2 years. We compared the ante-and postnatal characteristics and exposures of the 65 infants with a VFD to their peers who did not have a VFD. We used time-oriented logistic regression risk models to assess the associations of potential antecedents and correlates with a VFD.

RESULTS

In the final regression model, VFD was associated with maternal consumption of aspirin during the current pregnancy, recurring/persistent acidemia during the first 3 postnatal days, cerebral ventriculomegaly seen on neonatal ultrasound, prethreshold retinopathy of prematurity (ROP), and supplemental oxygen and ventilator dependence at 36 weeks post-menstrual age. Birth before the 27th week was also associated with increased risk, but its significance was diminished by the addition of postnatal variables.

CONCLUSION

In this sample of extremely preterm born infants, antenatal as well as early and late postnatal characteristics and exposures are associated with an increased risk of having a VFD. Our study adds to our knowledge about the complex etiology of visual deficits of prematurity, and supports a multifactorial cause of these deficits.

Pulmonary surfactant protein a is expressed in mouse retina by Müller cells and impacts neovascularization in oxygen-induced retinopathy

PURPOSE

Surfactant protein A (SP-A) up-regulates cytokine expression in lung disease of prematurity. Here we present data that for the first time characterizes SP-A expression and localization in the mouse retina and its impact on neovascularization (NV) in the mouse.

METHODS

Retinal SP-A was localized in wild-type (WT) mice with the cell markers glutamine synthetase (Müller cells), neurofilament-M (ganglion cells), glial acid fibrillary acid protein (astrocytes), and cluster of differentiation 31 (endothelial cells). Toll-like receptor 2 and 4 (TLR-2 and TLR-4) ligands were used to up-regulate SP-A expression in WT and myeloid differentiation primary response 88 (MyD88) protein (necessary for NFκB signaling) null mouse retinas and Müller cells, which were quantified using ELISA. Retinal SP-A was then measured in the oxygen-induced retinopathy (OIR) mouse model. The effect of SP-A on retinal NV was then studied in SP-A null (SP-A(-/-)) mice.

RESULTS

SP-A is present at birth in the WT mouse retina and colocalizes with glutamine synthetase. TLR-2 and TLR-4 ligands increase SP-A both in the retina and in Müller cells. SP-A is increased at postnatal day 17 (P17) in WT mouse pups with OIR compared to that in controls (P = 0.02), and SP-A(-/-) mice have reduced NV compared to WT mice (P = 0.001) in the OIR model.

CONCLUSIONS

Retinal and Müller cell SP-A is up-regulated via the NFκB pathway and up-regulated during the hypoxia phase of OIR. Absence of SP-A attenuates NV in the OIR model. Thus SP-A may be a marker of retinal inflammation during NV.

Genetic variants associated with severe retinopathy of prematurity in extremely low birth weight infants

PURPOSE

To determine genetic variants associated with severe retinopathy of prematurity (ROP) in a candidate gene cohort study of US preterm infants.

METHODS

Preterm infants in the discovery cohort were enrolled through the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network, and those in the replication cohort were from the University of Iowa. All infants were phenotyped for ROP severity. Because of differences in the durations of enrollment between cohorts, severe ROP was defined as threshold disease in the discovery cohort and as threshold disease or type 1 ROP in the replication cohort. Whole genome amplified DNA from stored blood spot samples from the Neonatal Research Network biorepository was genotyped using an Illumina GoldenGate platform for candidate gene single nucleotide polymorphisms (SNPs) involving angiogenic, developmental, inflammatory, and oxidative pathways. Three analyses were performed to determine significant epidemiologic variables and SNPs associated with levels of ROP severity. Analyses controlled for multiple comparisons, ancestral eigenvalues, family relatedness, and significant epidemiologic variables. Single nucleotide polymorphisms significantly associated with ROP severity from the discovery cohort were analyzed in the replication cohort and in meta-analysis.

RESULTS

Eight hundred seventeen infants in the discovery cohort and 543 in the replication cohort were analyzed. Severe ROP occurred in 126 infants in the discovery and in 14 in the replication cohort. In both cohorts, ventilation days and seizure occurrence were associated with severe ROP. After controlling for significant factors and multiple comparisons, two intronic SNPs in the gene BDNF (rs7934165 and rs2049046, P < 3.1 × 10(-5)) were associated with severe ROP in the discovery cohort and were not associated with severe ROP in the replication cohort. However, when the cohorts were analyzed together in an exploratory meta-analysis, rs7934165 increased in associated significance with severe ROP (P = 2.9 × 10(-7)).

CONCLUSIONS

Variants in BDNF encoding brain-derived neurotrophic factor were associated with severe ROP in a large candidate gene study of infants with threshold ROP.

Serum concentrations of cytokines in infants with retinopathy of prematurity

Retinopathy of prematurity (ROP) is the leading cause of blindness in preterm infants. In this study, we investigated the cytokine levels in cord blood of normal preterm neonates and preterm infants developed ROP. Serum levels of 10 cytokines in umbilical cord blood were measured by multiplex protein arrays from 62 healthy preterm neonates and 30 preterm neonate cases who developed ROP at later stage. Results showed that serum levels of cytokines including interleukin 7 (IL-7), monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein 1 alpha (MIP-1α), and macrophage inflammatory protein 1 beta (MIP-1β) were significantly increased in cases who developed ROP than in healthy preterm neonates (3.5-fold, 3.2-fold, 3.4-fold, and 2.1-fold, respectively), whereas levels of these four cytokines did not reveal any significant differences between healthy preterm infants and normal infants. When comparing the expression of cytokines in ROP patients with different clinical parameters, ROP cases whose gestational age at delivery earlier than 29.0 weeks demonstrated increased levels of MCP-1 and MIP-1β than those later than 29.0 weeks (p < 0.05). Also, ROP cases with birth weight less than 1.28 kg revealed significantly higher level of MIP-1β than those who were heavier than 1.28 kg (p < 0.05). These data indicated that levels of IL-7, MCP-1, MIP-1α, and MIP-1β were associated with increased risk of ROP, in which MIP-1β may be further correlated with the severity of ROP.

Oral propranolol for retinopathy of prematurity: risks, safety concerns, and perspectives

OBJECTIVE

To evaluate safety and efficacy of oral propranolol administration in preterm newborns affected by an early phase of retinopathy of prematurity (ROP).

STUDY DESIGN

Fifty-two preterm newborns with Stage 2 ROP were randomized to receive oral propranolol (0.25 or 0.5 mg/kg/6 hours) added to standard treatment or standard treatment alone. To evaluate safety of the treatment, hemodynamic and respiratory variables were continuously monitored, and blood samples were collected weekly to check for renal, liver, and metabolic balance. To evaluate efficacy of the treatment, the progression of the disease (number of laser treatments, number of bevacizumab treatments, and incidence of retinal detachment) was evaluated by serial ophthalmologic examinations, and plasma soluble E-selectin levels were measured weekly.

RESULTS

Newborns treated with propranolol showed less progression to Stage 3 (risk ratio 0.52; 95% CI 0.47-0.58, relative reduction of risk 48%) or Stage 3 plus (relative risk 0.42 95% CI 0.31-0.58, relative reduction of risk 58%). The infants required fewer laser treatments and less need for rescue treatment with intravitreal bevacizumab (relative risk 0.48; 95% CI 0.29-0.79, relative reduction of risk 52 %), a 100% relative reduction of risk for progression to Stage 4. They also had significantly lower plasma soluble E-selectin levels. However, 5 of the 26 newborns treated with propranolol had serious adverse effects (hypotension, bradycardia), in conjunction with episodes of sepsis, anesthesia induction, or tracheal stimulation.

CONCLUSION

This pilot study suggests that the administration of oral propranolol is effective in counteracting the progression of ROP but that safety is a concern.

Soluble ST2, a modulator of the inflammatory response, in preterm and term labor

OBJECTIVE

Intra-amniotic infection/inflammation (IAI) is causally linked with spontaneous preterm labor and delivery. The ST2L receptor and its soluble form (sST2) are capable of binding to interleukin (IL)-33, a member of the IL-1 superfamily. Members of this cytokine family have been implicated in the onset of spontaneous preterm labor in the context of infection. Soluble ST2 has anti-inflammatory properties, and plasma concentrations are elevated in systemic inflammation, such as sepsis, acute pyelonephritis in pregnancy and the fetal inflammatory response syndrome. The aims of this study were to examine: (1) whether amniotic fluid concentrations of sST2 change with IAI, preterm, and term parturition; and (2) if mRNA expression of ST2 in the chorioamniotic membranes changes with acute histologic chorioamnionitis in women who deliver preterm.

METHOD

A cross-sectional study was conducted to determine amniotic fluid concentrations of sST2 in: (1) women with preterm labor (PTL) who delivered at term (n=49); (2) women with PTL who delivered preterm without IAI (n=21); (3) women with PTL who delivered preterm with IAI (n=31); (4) term pregnancies not in labor (n=13); and (5) term pregnancies in labor (n=43). The amniotic fluid concentration of sST2 was determined by ELISA. The mRNA expression of ST2 in the chorioamniotic membranes of women who delivered preterm with (n=24), and without acute histologic chorioamnionitis (n=19) was determined by qRT-PCR.

RESULTS

(1) Patients with PTL who delivered preterm with IAI had a lower median amniotic fluid concentration of sST2 compared to those with PTL who delivered preterm without IAI [median 410 ng/mL, inter-quartile range (IQR) 152-699 ng/mL versus median 825 ng/mL, IQR 493-1216 ng/mL; p=0.0003] and those with PTL who delivered at term [median 410 ng/mL, IQR 152-699 ng/mL versus median 673 ng/mL, IQR 468-1045 ng/mL; p=0.0003]; (2) no significant differences in the median amniotic fluid concentration of sST2 were observed between patients with PTL who delivered at term and those who delivered preterm without IAI (p=0.4), and between women at term in labor and those at term not in labor (p=0.9); (3) the mean mRNA expression of ST2 was 4-fold lower in women who delivered preterm with acute histologic chorioamnionitis than in those without this lesion (p=0.008).

CONCLUSIONS

The median sST2 amniotic fluid concentration and mRNA expression of ST2 by chorioamniotic membranes is lower in PTL associated with IAI and acute histologic chorioamnionitis than in PTL without these conditions. Changes in the median amniotic fluid sST2 concentration are not observed in preterm and term parturition without IAI. Thus, amniotic fluid sST2 in the presence of IAI behaves differently when compared to sST2 in the plasma of individuals affected by fetal inflammatory response syndrome, acute pyelonephritis in pregnancy, and adult sepsis. Decreased concentrations of sST2 in IAI are likely to promote a pro-inflammatory response, which is important for parturition in the context of infection.

Retinopathy of prematurity

The immature retinas of preterm neonates are susceptible to insults that disrupt neurovascular growth, leading to retinopathy of prematurity. Suppression of growth factors due to hyperoxia and loss of the maternal-fetal interaction result in an arrest of retinal vascularisation (phase 1). Subsequently, the increasingly metabolically active, yet poorly vascularised, retina becomes hypoxic, stimulating growth factor-induced vasoproliferation (phase 2), which can cause retinal detachment. In very premature infants, controlled oxygen administration reduces but does not eliminate retinopathy of prematurity. Identification and control of factors that contribute to development of retinopathy of prematurity is essential to prevent progression to severe sight-threatening disease and to limit comorbidities with which the disease shares modifiable risk factors. Strategies to prevent retinopathy of prematurity will depend on optimisation of oxygen saturation, nutrition, and normalisation of concentrations of essential factors such as insulin-like growth factor 1 and ω-3 polyunsaturated fatty acids, as well as curbing of the effects of infection and inflammation to promote normal growth and limit suppression of neurovascular development.

Dopamine-resistant hypotension and severe retinopathy of prematurity

OBJECTIVE

To examine the relationship between the cause or severity of hypotension and the development of severe ROP (sROP) (≥stage 3 or stage 2 with plus disease in zone I or II).

STUDY DESIGN

Infants (<28 weeks' gestation, n = 242) were observed for hypotension and treated with a standardized hypotension-treatment protocol. Hypotension was classified as resulting from one of the following causes: (1) culture-positive infection and/or necrotizing enterocolitis; (2) patent ductus arteriosus ligation; or (3) "idiopathic" (no cause identified other than prematurity), and as being either dopamine responsive or dopamine resistant. Cortisol levels were measured for infants with dopamine-resistant hypotension. Eye examinations were performed until the retinopathy of prematurity resolved or the vasculature matured. Multivariable logistic regression analysis was performed to determine the relationship between the cause/severity of hypotension and sROP.

RESULTS

Overall, 66% of infants developed hypotension (41% were dopamine responsive and 25% were dopamine resistant). sROP developed in 19% of infants. "Idiopathic" dopamine-resistant hypotension was the only cause significantly related to sROP. Of the infants with dopamine-resistant hypotension, 66% had low serum cortisol (≤10 μg/dL). Low cortisol, in the presence of dopamine-resistant hypotension, was significantly associated with sROP and accounted for the relationship between "idiopathic" hypotension and sROP. When low cortisol was included in statistical models, other known risk factors, such as immature gestation, were no longer significantly related to sROP.

CONCLUSION

Low cortisol, in the presence of dopamine-resistant hypotension, has the greatest magnitude of association with sROP.

Characterization of the fetal blood transcriptome and proteome in maternal anti-fetal rejection: evidence of a distinct and novel type of human fetal systemic inflammatory response

BACKGROUND

The human fetus is able to mount a systemic inflammatory response when exposed to microorganisms. This stereotypic response has been termed the 'fetal inflammatory response syndrome' (FIRS), defined as an elevation of fetal plasma interleukin-6 (IL-6). FIRS is frequently observed in patients whose preterm deliveries are associated with intra-amniotic infection, acute inflammatory lesions of the placenta, and a high rate of neonatal morbidity. Recently, a novel form of fetal systemic inflammation, characterized by an elevation of fetal plasma CXCL10, has been identified in patients with placental lesions consistent with 'maternal anti-fetal rejection'. These lesions include chronic chorioamnionitis, plasma cell deciduitis, and villitis of unknown etiology. In addition, positivity for human leukocyte antigen (HLA) panel-reactive antibodies (PRA) in maternal sera can also be used to increase the index of suspicion for maternal anti-fetal rejection. The purpose of this study was to determine (i) the frequency of pathologic lesions consistent with maternal anti-fetal rejection in term and spontaneous preterm births; (ii) the fetal serum concentration of CXCL10 in patients with and without evidence of maternal anti-fetal rejection; and (iii) the fetal blood transcriptome and proteome in cases with a fetal inflammatory response associated with maternal anti-fetal rejection.

METHOD OF STUDY

Maternal and fetal sera were obtained from normal term (n = 150) and spontaneous preterm births (n = 150). A fetal inflammatory response associated with maternal anti-fetal rejection was diagnosed when the patients met two or more of the following criteria: (i) presence of chronic placental inflammation; (ii) ≥80% of maternal HLA class I PRA positivity; and (iii) fetal serum CXCL10 concentration >75th percentile. Maternal HLA PRA was analyzed by flow cytometry. The concentrations of fetal CXCL10 and IL-6 were determined by ELISA. Transcriptome analysis was undertaken after the extraction of total RNA from white blood cells with a whole-genome DASL assay. Proteomic analysis of fetal serum was conducted by two-dimensional difference gel electrophoresis. Differential gene expression was considered significant when there was a P < 0.01 and a fold-change >1.5.

RESULTS

(i) The frequency of placental lesions consistent with maternal anti-fetal rejection was higher in patients with preterm deliveries than in those with term deliveries (56% versus 32%; P < 0.001); (ii) patients with spontaneous preterm births had a higher rate of maternal HLA PRA class I positivity than those who delivered at term (50% versus 32%; P = 0.002); (iii) fetuses born to mothers with positive maternal HLA PRA results had a higher median serum CXCL10 concentration than those with negative HLA PRA results (P < 0.001); (iv) the median serum CXCL10 concentration (but not IL-6) was higher in fetuses with placental lesions associated with maternal anti-fetal rejection than those without such lesions (P < 0.001); (v) a whole-genome DASL assay of fetal blood RNA demonstrated differential expression of 128 genes between fetuses with and without lesions associated with maternal anti-fetal rejection; and (vi) comparison of the fetal serum proteome demonstrated 20 proteins whose abundance differed between fetuses with and without lesions associated with maternal anti-fetal rejection.

CONCLUSION

We describe a systemic inflammatory response in human fetuses born to mothers with evidence of maternal anti-fetal rejection. The transcriptome and proteome of this novel type of fetal inflammatory response were different from that of FIRS type I (which is associated with acute infection/inflammation).

Soluble ST2 in the fetal inflammatory response syndrome: in vivo evidence of activation of the anti-inflammatory limb of the immune response

OBJECTIVE

Inflammation is a mechanism of host response to infection, which can be harmful when inappropriately modulated. Soluble ST2 (sST2) is a decoy receptor of interleukin (IL)-33, and this complex modulates the balance in the Th1/Th2 immune response. Moreover, sST2 inhibits the production of pro-inflammatory cytokines in cooperation with an anti-inflammatory cytokine, IL-10. The objectives of this study were to: (1) determine whether umbilical cord plasma sST2 concentration differs between preterm neonates with and without funisitis and between those with and without the fetal inflammatory response syndrome (FIRS); and (2) evaluate the relationship between sST2 and IL-10 among neonates with funisitis and/or FIRS.

METHODS

Umbilical cord plasma was collected from neonates delivered prematurely due to preterm labor or preterm prelabor rupture of membranes with (n = 36), and without funisitis (n = 30). FIRS (umbilical cord IL-6 concentration ≥ 17.5 pg/mL) was identified in 29 neonates. Plasma sST2 and IL-10 concentrations were determined by enzyme linked immune sorbent assay.

RESULTS

The median umbilical cord plasma sST2 concentration was 6.7-fold higher in neonates with FIRS than in those without FIRS (median 44.6 ng/mL, interquartile range (IQR) 13.8-80.3 ng/mL versus median 6.7 ng/mL, IQR 5.6-20.1 ng/mL; p < 0.0001). Similarly, the median umbilical cord plasma sST2 concentration was 2.7-fold higher in neonates with funisitis than in those without funisitis (median 19.1 ng/mL; IQR 7.1-75.0 ng/mL versus median 7.2 ng/mL; IQR 5.9-23.1 ng/mL; p = 0.008). There was a strong positive correlation between sST2 and IL-10 in neonates with funisitis and/or FIRS (Spearman's Rho = 0.7, p < 0.0001).

CONCLUSION

FIRS and funisitis are associated with an elevation of umbilical cord plasma concentrations of soluble ST2. This protein represents an important mediator of the immune response in neonates diagnosed with FIRS by promoting an anti-inflammatory effect in association with IL-10.

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.