Opportunistic dried blood spot sampling validates and optimizes a pediatric population pharmacokinetic model of metronidazole.

Pharmacokinetic models rarely undergo external validation in vulnerable populations such as critically ill infants, thereby limiting the accuracy, efficacy, and safety of model-informed dosing in real-world settings. Here, we describe an opportunistic approach using dried blood spots (DBS) to evaluate a population pharmacokinetic model of metronidazole in critically ill preterm infants of gestational age (GA) ≤31 weeks from the Metronidazole Pharmacokinetics in Premature Infants (PTN_METRO, NCT01222585) study. First, we used linear correlation to compare 42 paired DBS and plasma metronidazole concentrations from 21 preterm infants [mean (SD): post natal age 28.0 (21.7) days, GA 26.3 (2.4) weeks]. Using the resulting predictive equation, we estimated plasma metronidazole concentrations (ePlasma) from 399 DBS collected from 122 preterm and term infants [mean (SD): post natal age 16.7 (15.8) days, GA 31.4 (5.1) weeks] from the Antibiotic Safety in Infants with Complicated Intra-Abdominal Infections (SCAMP, NCT01994993) trial. When evaluating the PTN_METRO model using ePlasma from the SCAMP trial, we found that the model generally predicted ePlasma well in preterm infants with GA ≤31 weeks. When including ePlasma from term and preterm infants with GA >31 weeks, the model was optimized using a sigmoidal Emax maturation function of postmenstrual age on clearance and estimated the exponent of weight on volume of distribution. The optimized model supports existing dosing guidelines and adds new data to support a 6-hour dosing interval for infants with postmenstrual age >40 weeks. Using an opportunistic DBS to externally validate and optimize a metronidazole population pharmacokinetic model was feasible and useful in this vulnerable population.

Bronchopulmonary dysplasia is associated with polyhydramnios in a scan for novel perinatal risk factors.

BACKGROUND: The pathogenesis of bronchopulmonary dysplasia (BPD) is multifactorial, and there are limited data about prenatal exposures and risk of BPD. STUDY DESIGN: Our study performed parallel analyses using a logistic regression model in a cohort of 4527 infants with data from a curated registry and using a phenome wide association study (PheWAS) based on ICD9/10-based phecodes. We examined 20 prenatal exposures from a neonatal intensive care unit (NICU) curated registry database related to pregnancy and maternal health as well as 94 maternal diagnosis phecodes with a PheWAS analysis. RESULT: In both the curated registry and PheWAS analyses, polyhydramnios was associated with an increased risk of BPD (OR 5.70, 95% CI 2.78-11.44, p = 1.37 × 10-6). CONCLUSION: Our data suggest that polyhydramnios may be a clinical indicator of premature infants at increased risk for bronchopulmonary dysplasia. Combining curated registry data with PheWAS analysis creates a valuable tool to generate hypotheses. IMPACT: Polyhydramnios was significantly associated with bronchopulmonary dysplasia in both a curated registry and by ICD coding analysis with a phenome wide association study (PheWAS). Preterm polyhydramnios may be a clinical indicator of infants at increased risk for developing bronchopulmonary dysplasia after preterm birth. Combining curated registry with PheWAS analysis creates a valuable tool to generate hypotheses about perinatal risk factors and morbidities associated with preterm birth.

Trial of Erythropoietin for Hypoxic-Ischemic Encephalopathy in Newborns.

BACKGROUND: Neonatal hypoxic-ischemic encephalopathy is an important cause of death as well as long-term disability in survivors. Erythropoietin has been hypothesized to have neuroprotective effects in infants with hypoxic-ischemic encephalopathy, but its effects on neurodevelopmental outcomes when given in conjunction with therapeutic hypothermia are unknown. METHODS: In a multicenter, double-blind, randomized, placebo-controlled trial, we assigned 501 infants born at 36 weeks or more of gestation with moderate or severe hypoxic-ischemic encephalopathy to receive erythropoietin or placebo, in conjunction with standard therapeutic hypothermia. Erythropoietin (1000 U per kilogram of body weight) or saline placebo was administered intravenously within 26 hours after birth, as well as at 2, 3, 4, and 7 days of age. The primary outcome was death or neurodevelopmental impairment at 22 to 36 months of age. Neurodevelopmental impairment was defined as cerebral palsy, a Gross Motor Function Classification System level of at least 1 (on a scale of 0 [normal] to 5 [most impaired]), or a cognitive score of less than 90 (which corresponds to 0.67 SD below the mean, with higher scores indicating better performance) on the Bayley Scales of Infant and Toddler Development, third edition. RESULTS: Of 500 infants in the modified intention-to-treat analysis, 257 received erythropoietin and 243 received placebo. The incidence of death or neurodevelopmental impairment was 52.5% in the erythropoietin group and 49.5% in the placebo group (relative risk, 1.03; 95% confidence interval [CI], 0.86 to 1.24; P = 0.74). The mean number of serious adverse events per child was higher in the erythropoietin group than in the placebo group (0.86 vs. 0.67; relative risk, 1.26; 95% CI, 1.01 to 1.57). CONCLUSIONS: The administration of erythropoietin to newborns undergoing therapeutic hypothermia for hypoxic-ischemic encephalopathy did not result in a lower risk of death or neurodevelopmental impairment than placebo and was associated with a higher rate of serious adverse events. (Funded by the National Institute of Neurological Disorders and Stroke; ClinicalTrials.gov number, NCT02811263.).

Parental Enrollment Decision-Making for a Neonatal Clinical Trial.

OBJECTIVE: To describe the parental experience of recruitment and assess differences between parents who participated and those who declined to enroll in a neonatal clinical trial. STUDY DESIGN: This was a survey conducted at 12 US neonatal intensive care units of parents of infants who enrolled in the High-dose Erythropoietin for Asphyxia and encephaLopathy (HEAL) trial or who were eligible but declined enrollment. Questions assessed 6 factors of the parental experience of recruitment: (1) interactions with research staff; (2) the consent experience; (3) perceptions of the study; (4) decisional conflict; (5) reasons for/against participation; and (6) timing of making the enrollment decision. RESULTS: In total, 269 of 387 eligible parents, including 183 of 242 (75.6%) of those who enrolled their children in HEAL and 86 of 145 (59.3%) parents who declined to enroll their children in HEAL, were included in analysis. Parents who declined to enroll more preferred to be approached by clinical team members rather than by research team members (72.9% vs 49.2%, P = .005). Enrolled parents more frequently reported positive initial impressions (54.9% vs 10.5%, P < .001). Many parents in both groups made their decision early in the recruitment process. Considerations of reasons for/against participation differed by enrollment status. CONCLUSIONS: Understanding how parents experience recruitment, and how this differs by enrollment status, may help researchers improve recruitment processes for families and increase enrollment. The parental experience of recruitment varied by enrollment status. These findings can guide future work aiming to inform optimal recruitment strategies for neonatal clinical trials.

Acute and Chronic Placental Abnormalities in a Multicenter Cohort of Newborn Infants with Hypoxic-Ischemic Encephalopathy.

OBJECTIVE: To examine the frequency of placental abnormalities in a multicenter cohort of newborn infants with hypoxic-ischemic encephalopathy (HIE) and to determine the association between acuity of placental abnormalities and clinical characteristics of HIE. STUDY DESIGN: Infants born at ≥36 weeks of gestation (n = 500) with moderate or severe HIE were enrolled in the High-dose Erythropoietin for Asphyxia and Encephalopathy Trial. A placental pathologist blinded to clinical information reviewed clinical pathology reports to determine the presence of acute and chronic placental abnormalities using a standard classification system. RESULTS: Complete placental pathologic examination was available for 321 of 500 (64%) trial participants. Placental abnormalities were identified in 273 of 321 (85%) and were more common in infants ≥40 weeks of gestation (93% vs 81%, P = .01). A combination of acute and chronic placental abnormalities (43%) was more common than either acute (20%) or chronic (21%) abnormalities alone. Acute abnormalities included meconium staining of the placenta (41%) and histologic chorioamnionitis (39%). Chronic abnormalities included maternal vascular malperfusion (25%), villitis of unknown etiology (8%), and fetal vascular malperfusion (6%). Infants with chronic placental abnormalities exhibited a greater mean base deficit at birth (-15.9 vs -14.3, P = .049) than those without such abnormalities. Patients with HIE and acute placental lesions had older mean gestational ages (39.1 vs 38.0, P < .001) and greater rates of clinically diagnosed chorioamnionitis (25% vs 2%, P < .001) than those without acute abnormalities. CONCLUSIONS: Combined acute and chronic placental abnormalities were common in this cohort of infants with HIE, underscoring the complex causal pathways of HIE. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02811263.

Parental Factors Associated With the Decision to Participate in a Neonatal Clinical Trial.

Importance: It remains poorly understood how parents decide whether to enroll a child in a neonatal clinical trial. This is particularly true for parents from racial or ethnic minority populations. Understanding factors associated with enrollment decisions may improve recruitment processes for families, increase enrollment rates, and decrease disparities in research participation. Objective: To assess differences in parental factors between parents who enrolled their infant and those who declined enrollment for a neonatal randomized clinical trial. Design, Setting, and Participants: This survey study conducted from July 2017 to October 2019 in 12 US level 3 and 4 neonatal intensive care units included parents of infants who enrolled in the High-dose Erythropoietin for Asphyxia and Encephalopathy (HEAL) trial or who were eligible but declined enrollment. Data were analyzed October 2019 through July 2020. Exposure: Parental choice of enrollment in neonatal clinical trial. Main Outcomes and Measures: Percentages and odds ratios (ORs) of parent participation as categorized by demographic characteristics, self-assessment of child's medical condition, study comprehension, and trust in medical researchers. Survey questions were based on the hypothesis that parents who enrolled their infant in HEAL differ from those who declined enrollment across 4 categories: (1) infant characteristics and parental demographic characteristics, (2) perception of infant's illness, (3) study comprehension, and (4) trust in clinicians and researchers. Results: Of a total 387 eligible parents, 269 (69.5%) completed the survey and were included in analysis. This included 183 of 242 (75.6%) of HEAL-enrolled and 86 of 145 (59.3%) of HEAL-declined parents. Parents who enrolled their infant had lower rates of Medicaid participation (74 [41.1%] vs 47 [55.3%]; P = .04) and higher rates of annual income greater than $55 000 (94 [52.8%] vs 30 [37.5%]; P = .03) compared with those who declined. Black parents had lower enrollment rates compared with White parents (OR, 0.35; 95% CI, 0.17-0.73). Parents who reported their infant's medical condition as more serious had higher enrollment rates (OR, 5.7; 95% CI, 2.0-16.3). Parents who enrolled their infant reported higher trust in medical researchers compared with parents who declined (mean [SD] difference, 5.3 [0.3-10.3]). There was no association between study comprehension and enrollment. Conclusions and Relevance: In this study, the following factors were associated with neonatal clinical trial enrollment: demographic characteristics (ie, race/ethnicity, Medicaid status, and reported income), perception of illness, and trust in medical researchers. Future work to confirm these findings and explore the reasons behind them may lead to strategies for better engaging underrepresented groups in neonatal clinical research to reduce enrollment disparities.

Blood metabolomics in infants enrolled in a dose escalation pilot trial of budesonide in surfactant.

BACKGROUND: The pathogenesis of BPD includes inflammation and oxidative stress in the immature lung. Corticosteroids improve respiratory status and outcome, but the optimal treatment regimen for benefit with low systemic effects is uncertain. METHODS: In a pilot dose escalation trial, we administered ≤5 daily doses of budesonide in surfactant to 24 intubated premature infants (Steroid And Surfactant in ELGANs (SASSIE)). Untargeted metabolomics was performed on dried blood spots using UPLC-MS/MS. Tracheal aspirate IL-8 concentration was determined as a measure of lung inflammation. RESULTS: Metabolomics data for 829 biochemicals were obtained on 121 blood samples over 96 h from 23 infants receiving 0.025, 0.05, or 0.1 mg budesonide/kg. Ninety metabolites were increased or decreased in a time- and dose-dependent manner at q ≤ 0.1 with overrepresentation in lipid and amino acid super pathways. Different dose response patterns occurred, with negative regulation associated with highest sensitivity to budesonide. Baseline levels of 22 regulated biochemicals correlated with lung inflammation (IL-8), with highest significance for sphingosine and thiamin. CONCLUSIONS: Numerous metabolic pathways are regulated in a dose-dependent manner by glucocorticoids, which apparently act via distinct mechanisms that impact dose sensitivity. The findings identify candidate blood biochemicals as biomarkers of lung inflammation and systemic responses to corticosteroids. IMPACT: Treatment of premature infants in respiratory failure with 0.1 mg/kg intra-tracheal budesonide in surfactant alters levels of ~11% of detected blood biochemicals in discrete time- and dose-dependent patterns. A subset of glucocorticoid-regulated biochemicals is associated with lung inflammatory status as assessed by lung fluid cytokine concentration. Lower doses of budesonide in surfactant than currently used may provide adequate anti-inflammatory responses in the lung with fewer systemic effects, improving the benefit:risk ratio.

Dose-escalation trial of budesonide in surfactant for prevention of bronchopulmonary dysplasia in extremely low gestational age high-risk newborns (SASSIE).

BACKGROUND: Initial trials of lung-targeted budesonide (0.25 mg/kg) in surfactant to prevent bronchopulmonary dysplasia (BPD) in premature infants have shown benefit; however, the optimal safe dose is unknown. METHODS: Dose-escalation study of budesonide (0.025, 0.05, 0.10 mg/kg) in calfactatant in extremely low gestational age neonates (ELGANs) requiring intubation at 3-14 days. Tracheal aspirate (TA) cytokines, blood budesonide concentrations, and untargeted blood metabolomics were measured. Outcomes were compared with matched infants receiving surfactant in the Trial Of Late SURFactant (TOLSURF). RESULTS: Twenty-four infants with mean gestational age 25.0 weeks and 743 g birth weight requiring mechanical ventilation were enrolled at mean age 6 days. Budesonide was detected in the blood of all infants with a half-life of 3.4 h. Of 11 infants with elevated TA cytokine levels at baseline, treatment was associated with sustained decrease (mean 65%) at all three dosing levels. There were time- and dose-dependent decreases in blood cortisol concentrations and changes in total blood metabolites. Respiratory outcomes did not differ from the historic controls. CONCLUSIONS: Budesonide/surfactant had no clinical respiratory benefit at any dosing levels for intubated ELGANs. One-tenth the dose used in previous trials had minimal systemic metabolic effects and appeared effective for lung-targeted anti-inflammatory action.

Osteopontin and iCD8α Cells Promote Intestinal Intraepithelial Lymphocyte Homeostasis.

Intestinal intraepithelial lymphocytes (IEL) comprise a diverse population of cells residing in the epithelium at the interface between the intestinal lumen and the sterile environment of the lamina propria. Because of this anatomical location, IEL are considered critical components of intestinal immune responses. Indeed, IEL are involved in many different immunological processes, ranging from pathogen control to tissue stability. However, despite their critical importance in mucosal immune responses, very little is known about the homeostasis of different IEL subpopulations. The phosphoprotein osteopontin is important for critical physiological processes, including cellular immune responses, such as survival of Th17 cells and homeostasis of NK cells among others. Because of its impact in the immune system, we investigated the role of osteopontin in the homeostasis of IEL. In this study, we report that mice deficient in the expression of osteopontin exhibit reduced numbers of the IEL subpopulations TCRγδ+, TCRß+CD4+, TCRß+CD4+CD8α+, and TCRß+CD8αα+ cells in comparison with wild-type mice. For some IEL subpopulations, the decrease in cell numbers could be attributed to apoptosis and reduced cell division. Moreover, we show in vitro that exogenous osteopontin stimulates the survival of murine IEL subpopulations and unfractionated IEL derived from human intestines, an effect mediated by CD44, a known osteopontin receptor. We also show that iCD8α IEL but not TCRγδ+ IEL, TCRß+ IEL, or intestinal epithelial cells, can promote survival of different IEL populations via osteopontin, indicating an important role for iCD8α cells in the homeostasis of IEL.

Meningitis, urinary tract, and bloodstream infections in very low birth weight infants enrolled in a heart rate characteristics monitoring trial.

BACKGROUND: Displaying heart rate characteristic (HRC) scores was associated with lower sepsis-associated mortality in very low birth weight (VLBW) infants in a multicenter randomized controlled trial (HeRO trial). The aim of this study was to test whether HRC indices rise before diagnosis of urinary tract infection (UTI) or meningitis, with and without concomitant BSI. METHODS: Blood, urine, and cerebrospinal fluid (CSF) culture data after 3 days of age and within 120 days of study enrollment were analyzed from 2989 VLBW infants. The HRC index was analyzed 12 h prior to positive cultures compared to 36 h prior, using paired signed-rank tests. RESULTS: UTI, meningitis, and BSI were diagnosed in 10%, 2%, and 24% of infants, respectively. The mean hourly HRC index was significantly higher 12 h prior to diagnosis of UTI and BSI compared to 36 h prior (UTI 2.07 versus 1.81; BSI 2.62 versus 2.25, both p < 0.0001). The baseline HRC index was higher for meningitis, compared to UTI or BSI, but without a statistically significant rise in the day prior to meningitis diagnosis. CONCLUSIONS: In a large cohort of VLBW infants enrolled in the HeRO trial, the HRC index increased in the 24-h period prior to diagnosis of UTI and BSI but not meningitis.

Procalcitonin versus C-reactive protein: review of kinetics and performance for diagnosis of neonatal sepsis.

Procalcitonin (PCT) and C-reactive protein (CRP) are commonly used biomarkers, but their diagnostic advantage for neonatal early-onset (EOS) or late-onset (LOS) sepsis is controversial. In a comprehensive literature review we found significant heterogeneity between studies in sample timing, cut-off values, consideration of blood culture results for sepsis classification, and definition of EOS versus LOS. We identified 39 studies directly comparing PCT with CRP, but only four in very low birth weight (VLBW) neonates. The mean sensitivity for EOS, LOS, and EOS + LOS was 73.6%, 88.9%, and 76.5% for PCT, compared to 65.6%, 77.4%, and 66.4% for CRP, respectively. Mean specificity of PCT and CRP was 82.8% versus 82.7% for EOS, 75.6% versus 81.7% for LOS, and 80.4% versus 91.3% for EOS + LOS. More studies directly comparing both biomarkers for EOS and LOS, especially in extremely and very-low-birth-weight infants, are needed to determine their clinical value for guidance of antibiotic therapy in neonatal sepsis.

Innate and adaptive immunity in necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) is the most frequent and devastating gastrointestinal disease of premature infants. Although the precise mechanisms are not fully understood, NEC is thought to develop following a combination of prematurity, formula feeding, and adverse microbial colonization. Within the last decade, studies increasingly support an important role of a heightened mucosal immune response initiating a pro-inflammatory signaling cascade, which can lead to the disruption of the intestinal epithelium and translocation of pathogenic species. In this review, we first describe the cellular composition of the intestinal epithelium and its critical role in maintaining epithelial integrity. We then discuss cell signaling during NEC, specifically, toll-like receptors and nucleotide oligomerization domain-like receptors. We further review cytokines and cellular components that characterize the innate and adaptive immune systems and how they interact to support or modulate NEC development.

Variability in Immunization Practices for Preterm Infants.

INTRODUCTION: The Advisory Committee on Immunization Practices and the American Academy of Pediatrics (AAP) recommend the same immunization schedule for preterm and term infants. However, significant delays in vaccination of premature infants have been reported. OBJECTIVE: The objective of this study was to assess the variability of immunization practices in preterm infants. STUDY DESIGN: We conducted an online survey of 2,443 neonatologists in the United States, who are members of the Section for Neonatal-Perinatal Medicine of the AAP. Questions were targeted at immunization practices in the neonatal intensive care unit (NICU). RESULTS: Of the 420 responses (17%) received, 55% of providers administer the first vaccine at >2-month chronological age. Most providers (83%) surveyed reported delaying vaccines in the setting of clinical illness. Sixty percent reported increasing frequency of apnea-bradycardia events following immunization. More than half administer the initial vaccines over several days despite lack of supporting data. Reported considerations in delaying or spreading out 2-month vaccines were clinical instability, provider preference, lower gestational age, and lower birth weight. CONCLUSION: This survey substantiates the variability of immunizations practices in the NICU and identifies reasons for this variability. Future studies should inform better practice guidance for immunization of preterm NICU patients based on vaccine safety and effectiveness.

Monitoring neonates for ototoxicity.

OBJECTIVES: Neonates admitted to the neonatal intensive care unit (NICU) are at greater risk of permanent hearing loss compared to infants in well mother and baby units. Several factors have been associated with this increased prevalence of hearing loss, including congenital infections (e.g. cytomegalovirus or syphilis), ototoxic drugs (such as aminoglycoside or glycopeptide antibiotics), low birth weight, hypoxia and length of stay. The aetiology of this increased prevalence of hearing loss remains poorly understood. DESIGN: Here we review current practice and discuss the feasibility of designing improved ototoxicity screening and monitoring protocols to better identify acquired, drug-induced hearing loss in NICU neonates. STUDY SAMPLE: A review of published literature. CONCLUSIONS: We conclude that current audiological screening or monitoring protocols for neonates are not designed to adequately detect early onset of ototoxicity. This paper offers a detailed review of evidence-based research, and offers recommendations for developing and implementing an ototoxicity monitoring protocol for young infants, before and after discharge from the hospital.

Erythematous plaques and papules on a premature infant.

A 2240 gram boy was born at 33.2 weeks gestation with nonblanching, deeply erythematous plaques and papules on the back, flanks, and scalp (Figure 1). His mother was GBS positive and on antibiotic suppression for prior cutaneous MRSA and urinary tract infections. Intrapartum intravenous Penicillin G was administered, and the amniotic sac was artificially ruptured 4 hours prior to delivery to facilitate labor. The delivery was uncomplicated without concern for chorioamnionitis, but the patient initially required CPAP for respiratory distress with 1-minute and 5-minute Apgar scores of 7 and 8, respectively. A skin punch biopsy is shown (Figure 2).

In Utero Exposure to Histological Chorioamnionitis Primes the Exometabolomic Profiles of Preterm CD4+ T Lymphocytes.

Histological chorioamnionitis (HCA) is an intrauterine inflammatory condition that increases the risk for preterm birth, death, and disability because of persistent systemic and localized inflammation. The immunological mechanisms sustaining this response in the preterm newborn remain unclear. We sought to determine the consequences of HCA exposure on the fetal CD4+ T lymphocyte exometabolome. We cultured naive CD4+ T lymphocytes from HCA-positive and -negative preterm infants matched for gestational age, sex, race, prenatal steroid exposure, and delivery mode. We collected conditioned media samples before and after a 6-h in vitro activation of naive CD4+ T lymphocytes with soluble staphylococcal enterotoxin B and anti-CD28. We analyzed samples by ultraperformance liquid chromatography ion mobility-mass spectrometry. We determined the impact of HCA on the CD4+ T lymphocyte exometabolome and identified potential biomarker metabolites by multivariate statistical analyses. We discovered that: 1) CD4+ T lymphocytes exposed to HCA exhibit divergent exometabolomic profiles in both naive and activated states; 2) ∼30% of detected metabolites differentially expressed in response to activation were unique to HCA-positive CD4+ T lymphocytes; 3) metabolic pathways associated with glutathione detoxification and tryptophan degradation were altered in HCA-positive CD4+ T lymphocytes; and 4) flow cytometry and cytokine analyses suggested a bias toward a TH1-biased immune response in HCA-positive samples. HCA exposure primes the neonatal adaptive immune processes by inducing changes to the exometabolomic profile of fetal CD4+ T lymphocytes. These exometabolomic changes may link HCA exposure to TH1 polarization of the neonatal adaptive immune response.

Surgical necrotizing enterocolitis.

Although currently available data are variable, it appears that the incidence of surgical necrotizing enterocolitis (NEC) has not decreased significantly over the past decade. Pneumoperitoneum and clinical deterioration despite maximal medical therapy remain the most common indications for operative treatment. Robust studies linking outcomes with specific indications for operation are lacking. Promising biomarkers for severe NEC include fecal calprotectin and S100A12; serum fatty acid-binding protein; and urine biomarkers. Recent advances in ultrasonography make this imaging modality more useful in identifying surgical NEC and near-infrared spectroscopy (NIRS) is being actively studied. Another fairly recent finding is that regionalization of care for infants with NEC likely improves outcomes. The neurodevelopmental outcomes after surgical treatment are known to be poor. A randomized trial near completion will provide robust data regarding neurodevelopmental outcomes after laparotomy versus drainage as the initial operative treatment for severe NEC.