Defining necrotizing enterocolitis: current difficulties and future opportunities

Noninvasive Fecal Cytokine and Microbiota Profiles Predict Commencement of Necrotizing Enterocolitis in a Proof-of-Concept Study

Background and Aims

Necrotizing enterocolitis (NEC) is a life-threatening disease and the most common gastrointestinal emergency in premature infants. Accurate early diagnosis is challenging. Modified Bell's staging is routinely used to guide diagnosis, but early diagnostic signs are nonspecific, potentially leading to unobserved disease progression, which is problematic given the often rapid deterioration observed. We investigated fecal cytokine levels, coupled with gut microbiota profiles, as a noninvasive method to discover specific NEC-associated signatures that can be applied as potential diagnostic markers.

Methods

Premature babies born below 32 weeks of gestation were admitted to the 2-site neonatal intensive care unit (NICU) of Imperial College hospitals (St. Mary's or Queen Charlotte's & Chelsea) between January 2011 and December 2012. During the NICU stay, expert neonatologists grouped individuals by modified Bell's staging (healthy, NEC1, NEC2/3) and fecal samples from diapers were collected consecutively. Microbiota profiles were assessed by 16S rRNA gene amplicon sequencing and cytokine concentrations were measured by V-Plex multiplex assays.

Results

Early evaluation of microbiota profiles revealed only minor differences. However, at later time points, significant changes in microbiota composition were observed for Bacillota (adj. P = .0396), with Enterococcus being the least abundant in Bell stage 2/3 NEC. Evaluation of fecal cytokine levels revealed significantly higher concentrations of IL-1α (P = .045), IL-5 (P = .0074), and IL-10 (P = .032) in Bell stage 1 NEC compared to healthy individuals.

Conclusion

Differences in certain fecal cytokine profiles in patients with NEC indicate their potential use as diagnostic biomarkers to facilitate earlier diagnosis. Additionally, associations between microbial and cytokine profiles contribute to improving knowledge about NEC pathogenesis.

Effects of antimicrobials on the gastrointestinal microbiota of dogs and cats

Among several environmental factors, exposure to antimicrobials has been in the spotlight as a cause of profound and long-term disturbance of the intestinal microbiota. Antimicrobial-induced dysbiosis is a general term and includes decreases in microbial richness and diversity, loss of beneficial bacterial groups, blooms of intestinal pathogens and alterations in the metabolic functions and end-products of the microbiota. Mounting evidence from human and experimental animal studies suggest an association between antimicrobial-induced dysbiosis and susceptibility to gastrointestinal, metabolic, endocrine, immune and neuropsychiatric diseases. These associations are commonly stronger after early life exposure to antimicrobials, a period during which maturation of the microbiota and immune system take place in parallel. In addition, these associations commonly become stronger as the number of antimicrobial courses increases. The repeatability of these findings among different studies as well as the presence of a dose-dependent relationship between antimicrobial exposure and disease development collectively require careful consideration of the need for antimicrobial use. There are limited studies are available in dogs and cats regarding the long-term effects of antimicrobials on the microbiota and subsequent susceptibility to diseases. This review discusses the effects of antimicrobials on the gastrointestinal microbiota and the most important associations between antimicrobial-induced dysbiosis and diseases in humans, dogs, and cats.

Review of Necrotizing Enterocolitis and Spontaneous Intestinal Perforation Clinical Presentation, Treatment, and Outcomes

The Necrotizing Enterocolitis Surgery Trial (NEST) highlights the importance of distinguishing necrotizing enterocolitis (NEC) from spontaneous intestinal perforation (SIP) when developing surgical treatment plans. Further research is needed to increase the accuracy of this distinction, but even with our current abilities to do this initial laparotomy appears to be optimal for infants with presumed NEC. The preferred initial operation for those with SIP is more equivocal. Rates of NEC are likely decreasing slowly, whereas those with SIP are not. New imaging modalities, especially ultrasound, are becoming more useful but require more detailed investigation. Understanding the mechanisms causing these two conditions remains of paramount importance.

Associations between maternal residential rurality and maternal health, access to care, and very low birthweight infant outcomes

OBJECTIVE

Infant mortality is increased in isolated rural areas. This study compares prenatal factors, access to care, and health outcomes for very-low birthweight (VLBW) infants by degree of maternal residential rurality.

METHODS

This descriptive population-based retrospective cohort study used the California Perinatal Quality Care Collaborative registry to study VLBW infants. Rurality was assigned as urban, large rural, and small rural/isolated using the Rural Urban Commuting Area codes. We used hierarchical random effect models to test the association of rurality with survival without major morbidity.

RESULTS

The study included 38 614 dyads. VLBW survival without major morbidity decreased with increasing rurality and the relationship remained significant for small rural/isolated areas (OR 0.79, p = 0.03) after adjustment. Birth weight, gestational age, and infant sex were similar across geographic groups.

CONCLUSION

A rural urban disparity exists for VLBW survival without major morbidity. Our findings generate hypotheses about factors that may be driving these disparities.

Long-Term Outcome of Necrotizing Enterocolitis and Spontaneous Intestinal Perforation

OBJECTIVES

Necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP) are complications in preterm infants associated with high morbidity, mortality, impaired growth, and neurodevelopmental (ND) outcomes. Few studies have reported growth or ND outcomes of infants born extremely preterm with NEC/SIP beyond early childhood. Here, we compared anthropometric and ND outcomes, at 10 and 15 years, for children with medical NEC, surgical NEC, SIP, and neither NEC nor SIP.

METHODS

Participants from the prospective longitudinal extremely low gestational age newborns study were evaluated at ages 10 and 15 years for anthropometrics, neurocognition, attention-deficit/hyperactivity disorder, epilepsy, and gross motor function.

RESULTS

At age 10 years, 889 children were followed-up (medical NEC = 138, surgical NEC = 33, SIP = 29, no NEC/SIP = 689), and 694 children were followed up-at 15 years. Children with medical NEC had similar weight, BMI, height, and head circumference compared with controls at both 10 and 15 years. At 15 years, children with surgical NEC had lower weight z-score (adjusted β: -0.75, 95% confidence interval [CI]: -1.25 to -0.25), lower BMI z-score (adjusted β: -0.55, 95% CI: -1.09 to -0.01), and lower height z-score (adjusted β: -0.65, 95% CI: -1.16 to -0.14). Children with SIP had lower weight and height z-scores at age 10 years when adjusted for sample attrition, but these differences were not significant when adjusted for confounders. We observed no differences in long-term ND outcomes.

CONCLUSIONS

Surgical NEC- and SIP-associated growth impairment may persist through late childhood. ND outcomes among school-aged children born extremely preterm with any NEC or SIP are no different from children without NEC/SIP.

Data analytics in a clinical setting: Applications to understanding breathing patterns and their relevance to neonatal disease

In this review, we focus on the use of contemporary linear and non-linear data analytics as well as machine learning/artificial intelligence algorithms to inform treatment of pediatric patients. We specifically focus on methods used to quantify changes in breathing that can lead to increased risk for apnea of prematurity, retinopathy of prematurity (ROP), necrotizing enterocolitis (NEC) and provide a list of potentially useful algorithms that comprise a suite of software tools to enhance prediction of outcome. Next, we provide a brief overview of machine learning/artificial intelligence methods and applications within the sphere of perinatal care. Finally, we provide an overview of the infrastructure needed to use these tools in a clinical setting for real-time data acquisition, data synchrony, data storage and access, and bedside data visualization to assist in clinical decision making and support the medical informatics mission. Our goal is to provide an overview and inspire other investigators to adopt these tools for their own research and optimization of perinatal patient care.

Bedside Ultrasound for Early Diagnosis of Necrotizing Enterocolitis: A Pilot Study

OBJECTIVE

 This study aimed to assess whether bedside ultrasound (BUS) as the first imaging modality allows an earlier diagnosis of necrotizing enterocolitis (NEC) compared with abdominal radiography.

STUDY DESIGN

 A before-after controlled study in preterm infants with suspected NEC. The intervention group (October 2019-October 2021) received BUS as the first imaging modality and was managed accordingly to BUS findings. The control group (October 2015-September 2019) received radiography as the first imaging modality. The main outcome was NEC confirmation at the time of initial imaging. Secondary outcomes included time to diagnosis, laboratory data, and treatment requirements.

RESULTS

 Thirty-five episodes of suspected NEC with 14 (40%) confirmed NEC cases and 49 episodes of suspected NEC with 22 (44.9%) confirmed NEC cases were included in the intervention and control groups, respectively. In the intervention group, 11 of 14 (78.6%) NEC cases were confirmed at initial evaluation compared with 5 of 22 (22.7%) in the control group (p = 0.001). Infants in the intervention group developed thrombocytopenia and coagulopathy less frequently, were exposed to less radiation, and required less days of parenteral nutrition compared with the control group (p < 0.05).

CONCLUSION

 The use of BUS as the first imaging modality allowed an earlier diagnosis and timely treatment of NEC compared with abdominal radiography.Key Points · This is the first study that has assessed the role of BUS as the first imaging modality in NEC.. · BUS improves early diagnosis of NEC compared with abdominal radiography.. · BUS shortens time to NEC confirmation and treatment initiation which may reduce clinical severity of the NEC episode..

The Metabolome and the Gut Microbiota for the Prediction of Necrotizing Enterocolitis and Spontaneous Intestinal Perforation: A Systematic Review

Necrotizing enterocolitis (NEC) is the most devastating gastrointestinal emergency in preterm neonates. Research on early predictive biomarkers is fundamental. This is a systematic review of studies applying untargeted metabolomics and gut microbiota analysis to evaluate the differences between neonates affected by NEC (Bell’s stage II or III), and/or by spontaneous intestinal perforation (SIP) versus healthy controls. Five studies applying metabolomics (43 cases, 95 preterm controls) and 20 applying gut microbiota analysis (254 cases, 651 preterm controls, 22 term controls) were selected. Metabolomic studies utilized NMR spectroscopy or mass spectrometry. An early urinary alanine/histidine ratio >4 showed good sensitivity and predictive value for NEC in one study. Samples collected in proximity to NEC diagnosis demonstrated variable pathways potentially related to NEC. In studies applying untargeted gut microbiota analysis, the sequencing of the V3−V4 or V3 to V5 regions of the 16S rRNA was the most used technique. At phylum level, NEC specimens were characterized by increased relative abundance of Proteobacteria compared to controls. At genus level, pre-NEC samples were characterized by a lack or decreased abundance of Bifidobacterium. Finally, at the species level Bacteroides dorei, Clostridium perfringens and perfringens-like strains dominated early NEC specimens, whereas Clostridium butyricum, neonatale and Propionibacterium acnei those at disease diagnosis. Six studies found a lower Shannon diversity index in cases than controls. A clear separation of cases from controls emerged based on UniFrac metrics in five out of seven studies. Importantly, no studies compared NEC versus SIP. Untargeted metabolomics and gut microbiota analysis are interrelated strategies to investigate NEC pathophysiology and identify potential biomarkers. Expression of quantitative measurements, data sharing via biorepositories and validation studies are fundamental to guarantee consistent comparison of results.

Single-dose prophylactic ibuprofen therapy for patent ductus arteriosus in preterm infants

This study aimed to evaluate the short-term morbidities and efficacy of single-dose prophylactic intravenous ibuprofen for patent ductus arteriosus (PDA) on the first day of life in preterm infants. Data of 69 preterm infants with birth weight < 1250 g and gestational age < 30 weeks admitted to the neonatal intensive care unit were analyzed. Of these, 37 infants were assigned to the prophylactic treatment (PT) group and 32 were assigned to the nonprophylactic treatment (non-PT) group. Only the PT group administered intravenous ibuprofen (10 mg/kg) once within 6 hours after birth. Until postnatal day 7, ductal closure occurred in 11 (34.4%) infants in the non-PT group, and in 35 (94.6%) infants in the PT group, of which 30 (81.1%) infants had ductal closure on postnatal day 1. There were 2 (5.4%) infants in the PT group and 9 (28.1%) in the non-PT group who needed ibuprofen treatment due to moderate-to-large PDA after postnatal day 7. Preterm infants in the PT group were less likely to develop an intraventricular hemorrhage (≥grade 2) (adjusted odds ratio 0.007, 95% confidence interval 0.01-0.45), had a shorter duration of invasive ventilatory support and central venous catheter, and earlier postnatal age to achieve feeding of 50 and 100 mL/kg/day compared with those in the non-PT group. Single-dose prophylactic intravenous ibuprofen on the first day of life decreased the occurrence of a persistent PDA and intraventricular hemorrhage (≥grade 2), and reduced the duration of invasive ventilatory support, central venous catheter use, and hospital stay.

Survival of infants born at periviable gestation: The US national database

Background

Substantial differences exist in the approach to resuscitating infants born at periviable gestation. Evaluation of current survival may help guide prenatal counselling and provide accurate expectations of clinical outcomes. We aimed to assess the US national survival trends in periviable infants born at gestational age (GA) ≤24 weeks.

Methods

We used de-identified patient data obtained from the US Healthcare Cost and Utilization Project (HCUP) from 2007 to 2018. All infants with documented GA ≤24 weeks were included. The Cochran-Armitage test was used for trend analyses. Regression analyses were conducted for variables associated with survival.

Findings

A total of 44,628,827 infant records were identified with 124,345 (0.28%) infants born ≤24 weeks; of those, 77,050 infants <24 weeks and 47,295 infants had completed 24 weeks. Survival rates for infants <24 weeks and with completed 24 weeks were 15.4% and 71.6%, respectively, with higher survival over the years (Z = 9.438, P<0.001 & Z = 3.30, P<0.001, respectively). Survival was lower in males compared to females (aOR = 0.96, CI: 0.93-0.99 & aOR = 0.94, CI: 0.92-0.96, respectively) and with private insurance compared to public insurance (aOR = 0.74, CI: 0.71-0.77 & aOR = 0.67, CI: 0.65-0.69, respectively). Survival was higher when birth weight was >500 g compared to ≤500 g (aOR = 4.62, CI:3.23-5.02 & aOR = 5.44, CI: 4.59-5.84, respectively). Black (aOR = 1.33, CI: 1.31-1.36 & aOR = 1.24, CI: 1.20-1.32, respectively) and Hispanic (aOR = 1.29, CI: 1.27-1.32 & aOR = 1.27, CI: 1.22-1.30, respectively) had higher survival than White.

Interpretation

There is a national increase in survival over the years in infants born at periviable GA. BW >500 is associated with >4 folds higher survival compared to ≤500 g. The results of this study should be cautiously interpreted as long-term outcomes are unknown.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Cord blood antimicrobial peptide LL37 levels in preterm neonates and association with preterm complications

BACKGROUND

Cathelicidin/LL-37 plays a significant role in the human immune defense reaction. Preterm human immature organs being exposed to inflammation-induced injury was the critical denominator leading to the common preterm associated complications. Previous study showed LL37 concentration in preterm neonates was lower in tracheal aspirates and breast milk as compared to term infants. An adults study showed decreased LL-37 levels was a risk factor for patients in developing severe chronic obstructive pulmonary disease (COPD). However, little is known about the regulation of human cord blood LL37 in preterm neonates and the association with preterm complications. This study was designed to investigate the concentration of LL37 in cord blood of preterm infants and correlation with preterm complications.

METHODS

Singleton infants born in June 2017 to August 2021 in the study hospital were enrolled. Maternal and neonatal clinical characteristics were collected. LL37 levels, pro-inflammatory factor interleukin-6 (IL-6) and tumor necrosis factor-a (TNF-a) in cord blood and LL37 levels in serum 48-72 hours after birth were measured by enzyme-linked immunosorbent assay. The serum level of LL37 in preterm and term neonates were compared, the perinatal factors possibly affecting the LL37 levels were investigated and the relationship between LL37 level and preterm outcomes were analyzed.

RESULTS

Cord blood LL37 levels in preterm infants were lower than that in term neonates. Cord blood LL37 level was positively correlated with gestational age in preterm. Prenatal steroid administration in preterm neonates decreased cord blood LL37 level. LL37 level was obviously lower in patients with bronchopulmonary dysplasia (BPD). Multiple line regression analysis showed higher LL37 level in cord blood was an independent protective factor for BPD. The concentration of pro-inflammatory factor IL-6 was negatively correlated with LL37.

CONCLUSION

Cord blood LL37 levels increased during gestation and decreased after perinatal steroid usage. Very preterm infants who displayed higher cord blood LL37 level had reduced risk of developing BPD. Regulation of pro-inflammatory cytokine IL-6 may be associated with the protective effect of LL37 on BPD.

Necrotising enterocolitis, late-onset sepsis and mortality after routine probiotic introduction in the UK

OBJECTIVE

To compare necrotising enterocolitis (NEC), late-onset sepsis (LOS), focal intestinal perforation (FIP) and mortality in infants from a single neonatal unit before and after probiotic introduction.

DESIGN

Retrospective review of infants <32 weeks admitted January 2009-December 2012 (no probiotic) and January 2013-December 2017 (routine probiotics). Infants included were admitted before day 3, and not transferred out before day 3. NEC, LOS and FIP were defined with standard definitions.

PATIENTS

1061 infants were included, 509 preprobiotic and 552 postprobiotic. Median gestation, birth weight and antenatal steroid use did not differ, and proportions of extremely low birthweight infants were similar (37% and 41%).

RESULTS

Overall unadjusted risk of NEC (9.2% (95% CI 7.1 to 12.1) vs 10.6% (95% CI 8.2 to 13.4), p=0.48), LOS (16.3% (95% CI 13.2 to 19.6) vs 14.1% (95% CI 11.5 to 17.4), p=0.37) and mortality (9.2% (95% CI 7.1 to 12.1) vs 9.7% (95% CI 7.6 to 12.6), p=0.76) did not differ, nor proportion of surgical NEC. In multiple logistic regression, accounting for gestation, birth weight, antenatal steroid, maternal milk, chorioamnionitis and sex, probiotic receipt was not significantly associated with NEC (adjusted OR (aOR) 1.08 (95% CI 0.71 to 1.68), p=0.73), LOS or mortality. In subgroup (645 infants) >28 weeks, aOR for NEC in the probiotic cohort was 0.42 (95% CI 0.2 to 0.99, p=0.047). FIP was more common in the probiotic cohort (OR 2.3 (95% CI 1.0 to 5.4), p=0.04), not significant in regression analysis (2.11 (95% CI 0.97 to 4.95), p=0.05).

CONCLUSIONS

Probiotic use in this centre did not reduce overall mortality or rates of NEC, LOS or FIP but subgroup analysis identified NEC risk reduction in infants >28 weeks, and LOS reduction <28 weeks.

Bench to bedside - new insights into the pathogenesis of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the leading cause of death and disability from gastrointestinal disease in premature infants. Recent discoveries have shed light on a unifying theorem to explain the pathogenesis of NEC, suggesting that specific treatments might finally be forthcoming. A variety of experiments have highlighted how the interaction between bacterial signalling receptors on the premature intestine and an abnormal gut microbiota incites a pro-inflammatory response in the intestinal mucosa and its underlying endothelium that leads to NEC. Central amongst the bacterial signalling receptors implicated in NEC development is the lipopolysaccharide receptor Toll-like receptor 4 (TLR4), which is expressed at higher levels in the premature gut than in the full-term gut. The high prenatal intestinal expression of TLR4 reflects the role of TLR4 in the regulation of normal gut development, and supports additional studies indicating that NEC develops in response to signalling events that occur in utero. This Review provides new evidence explaining the pathogenesis of NEC, explores new findings indicating that NEC development has origins before birth, and discusses future questions and opportunities for discovery in this field.

A Yersiniabactin-producing Klebsiella aerogenes Strain Causing an Outbreak in an Austrian Neonatal Intensive Care Unit

BACKGROUND

Yersiniabactin, a siderophore with a high affinity to iron, has been described as a potential virulence factor in Enterobacteriaceae. Klebsiella aerogenes is a Gram-negative rod known to cause invasive infection in very low birth weight infants but is an unusual pathogen to cause outbreaks in neonatal intensive care units (NICU).

METHODS

We performed a retrospective analysis of all patients colonized with K. aerogenes in our NICU from September to December 2018. Each infant with an occurrence of K. aerogenes in any microbiological culture was defined as a case. Clinical data were taken from medical charts. K. aerogenes isolates were genotyped using whole-genome sequencing combined with core genome multilocus sequencing type analysis. Yersiniabactin production was evaluated by luciferase assay.

RESULTS

In total 16 patients were colonized with K. aerogenes over the 3-month period and 13 patients remained asymptomatic or developed late-onset neonatal sepsis from another pathogen. Three patients developed necrotizing enterocolitis, 2 complicated by sepsis and 1 of them died. All symptomatic patients were premature infants with low birth weight. Genetic sequencing confirmed an outbreak with the same strain, all samples expressed the high-pathogenicity island, necessary for the production of yersiniabactin. Six exemplary cases were proven to produce yersiniabactin in vitro.

CONCLUSION

This is the first report of an outbreak of a yersiniabactin-producing K. aerogenes strain causing invasive infection in preterm infants. We hypothesize that, due to improved iron uptake, this strain was associated with higher virulence than non-yersiniabactin-producing strains. Extended search for virulence factors and genetic sequencing could be pivotal in the management of NICU outbreaks in the future.

Novel Therapeutic Targeting of CCL3-CCR4 Axis Mediated Apoptotic Intesitnal Injury in Necrotizing Enterocolitis

Background

Necrotizing enterocolitis (NEC) is the leading cause of neonatal gastrointestinal-related death, while the etiology and pathogenesis are poorly understood.

Methods

The levels of CCL3 in intestinal tissue from modeling mice and patients were measured and analyzed. HE staining, TUNEL, Annexin and FCM were used to assess pathological changes and apoptosis in intestinal tissue and epithelial cells. CCL3, CCR4, cytokines, tight junction protein ZO-1, apoptosis-related genes and ERK1/2-NF-κB signaling pathway were detected by ELISA, Q-PCR, Western blotting and immunofluorescence.

Results

CCL3 levels in the intestinal tissue significantly elevated in patients with NEC and mouse models. Blockade of CCL3 significantly alleviated NEC-related intestinal tissue damage, while administration of recombinant CCL3 aggravated intestinal injury by exacerbating intestinal epithelial cell apoptosis in NEC mice. Importantly, CCR4 blockade reversed CCL3-mediated damage to intestinal tissue and intestinal epithelial cell apoptosis both in vivo and in vitro. Further mechanistic studies showed that CCL3 regulated apoptosis-related BAX/BCL-2 expression through the activation of the ERK1/2 and NF-κB pathways, which could be reversed by anti-CCR4 treatment. Furthermore, ERK1/2 inhibition reduced CCL3-mediated phosphorylation of NF-κB in IEC-6 cells, while inhibition of NF-κB had no obvious effect on ERK1/2 phosphorylation. As expected, inhibition of NF-κB regulated BAX/BCL-2 expression and alleviated CCL3-induced epithelial cell apoptosis. These results indicate that high expression of CCL3 in NEC lesions promotes intestinal epithelial apoptosis through the CCL3-CCR4-ERK1/2-NFκB-BAX/BCL2 signalling axis, thereby exacerbating NEC-related intestinal injury.

Conclusions

Our study represents an important conceptual advance that CCL3 may be one of the key culprits of intestinal tissue damage in NEC patients, and blocking either CCL3, CCR4, or NF-κB may represent a novel effective immunotherapy for NEC.

Point-of-Care (POC) Urinary L-Type Fatty Acid-Binding Protein (u-LFABP) Use in Critically Ill, Very Preterm Neonates

Preterm neonates are born with fewer functional nephrons, rendering them vulnerable to secondary insult. These insults are associated with acute kidney injury (AKI); thus, structural damage must be detected as early as possible. Urinary L-type fatty acid-binding protein (u-LFABP) has been proposed as a highly suitable kidney injury biomarker during prematurity. We aimed to analyze the use of POC u-LFABP in critically ill, very preterm neonates. This study was conducted at the neonatal intensive care unit (NICU), Dr. Cipto Mangunkusumo General Hospital, from November to December 2020. Baseline characteristics were recorded from electronic medical records. u-LFABP examination utilized stored urine samples from a previous study and was performed using a LFABP POC test kit. The proportion of abnormal u-LFABP (83.3%) was highest at 72 hours. Neonates with older gestational age (0–48 hours; $p=0.017$ ) and higher birth weight (0–48 hours; $p=0.022$ , 72 hours; $p=0.013$ ) had normal u-LFABP levels. Neonates exposed to nephrotoxic agents showed higher proportion of abnormal u-LFABP (0–48 hours; $p=0.006$ ). Longer invasive mechanical ventilation (IMV) period was observed in neonates with abnormal u-LFABP levels at 0–48 hours (7.44 ± 7.9 vs. 1.50 ± 2.9 days; $p=0.011$ ). We found an association between complication rates and poorer disease outcome trends with abnormal u-LFABP; however, this relationship was not supported statistically. In conclusion, this study demonstrated that u-LFABP can be detected using bedside POC kit in critically ill very preterm neonates and those exposed to nephrotoxic agents may be at risk for kidney injury, confirmed by abnormal u-LFABP levels.

Biomarkers of Necrotizing Enterocolitis: The Search Continues

Necrotizing enterocolitis (NEC) is the most common gastrointestinal (GI) emergency in the neonatal intensive care unit. Despite advances in medical care, mortality and morbidity from NEC have not changed. This is likely due to the lack of a clear understanding of this multifactorial disease, and reliable biomarkers for accurate diagnosis of NEC. Currently, the diagnosis of NEC is made by a combination of nonspecific clinical signs, symptoms, and radiological findings. Though biomarkers have been studied extensively, none offer an acceptable sensitivity or specificity to be used. This review will focus on the available literature on biomarkers for preterm NEC, acknowledging the limitations in studies including the variability of inclusion criteria, and most importantly, the lack of gold standard case definition for NEC.

Neonatal Pneumothorax in Late Preterm and Full-Term Newborns with respiratory Distress: A Single-Center Experience

Purpose: To evaluate the incidence rate, clinical characteristics, and perinatal outcomes of pneumothorax in late preterm and full-term newborns with respiratory distress and analyze the risk factors associated with pneumothorax.Methods: Infants born at ≥34 weeks’ gestation with respiratory distress and pneumothorax admitted between February 2014 and December 2020 were enrolled in this study. The pneumothorax group (n=36) was matched to the control group (n=144) in a 1:4 ratio, based on gestational age and birth weight. Risk factors were identified using logistic regression analysis with backward stepwise selection.Results: The incidence of pneumothorax during the study period was 1.36% (38/2,788). All patients were diagnosed with pneumothorax within 48 hours after birth, and increased oxygen demand was the most common symptom. The proportion of mortality and perinatal morbidity, such as intraventricular hemorrhage ≥grade 3, was significantly higher in the pneumothorax group than in the control group. The risk factors associated with pneumothorax were the need for positive pressure ventilation in the delivery room (odds ratio [OR], 3.40; 95% confidence interval [CI], 1.26 to 9.12; P=0.015) and a higher fraction of inspired oxygen to achieve an oxygen saturation of ≥90% on admission (OR, 1.06; 95% CI, 1.03 to 1.09; P<0.001).Conclusion: Pneumothorax should be suspected in late preterm and full-term newborns with respiratory distress within the first 3 days of life. Based on these risk factors, early diagnosis can reduce perinatal mortality and morbidity.

Using cluster analysis to describe phenotypical heterogeneity in extremely preterm infants: a retrospective whole-population study

OBJECTIVE

To use cluster analysis to identify discrete phenotypic groups of extremely preterm infants.

DESIGN

Secondary analysis of a retrospective whole population study.

SETTING

All neonatal units in England between 2014 and 2019.

PARTICIPANTS

Infants live-born at less than 28 weeks of gestation and admitted to a neonatal unit.

INTERVENTIONS

K-means cluster analysis was performed with the gestational age, Apgar score at 5 min and duration of mechanical ventilation as input variables.

PRIMARY AND SECONDARY OUTCOME MEASURES

Bronchopulmonary dysplasia, discharge on home oxygen, intraventricular haemorrhage, death before discharge from neonatal care.

RESULTS

Ten thousand one hundred and ninety-seven infants (53% male) were classified into four clusters: Cluster 1 contained infants with intermediate gestation and duration of ventilation and had an intermediate mortality and incidence of bronchopulmonary dysplasia. Cluster 2 contained infants with the highest gestation, a shorter duration of ventilation and the lowest mortality. Cluster 3 contained infants with the lowest Apgar score and highest mortality and incidence of intraventricular haemorrhage. Cluster 4 contained infants with the lowest gestation, longest duration of ventilation and highest incidence of bronchopulmonary dysplasia.

CONCLUSION

Clinical parameters can classify extremely preterm infants into discrete phenotypic groups with differing subsequent neonatal outcomes.

A critical evaluation of current definitions of necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is a devastating intestinal disease of premature infants, with significant mortality and long-term morbidity among survivors. Multiple NEC definitions exist, but no formal head-to-head evaluation has been performed. We hypothesized that contemporary definitions would perform better in evaluation metrics than Bell's and range features would be more frequently identified as important than yes/no features.

METHODS

Two hundred and nineteen patients from the University of Iowa hospital with NEC, intestinal perforation, or NEC concern were identified from a 10-year retrospective cohort. NEC presence was confirmed by a blinded investigator. Evaluation metrics were calculated using statistics and six supervised machine learning classifiers for current NEC definitions. Feature importance evaluation was performed on each decision tree classifier.

RESULTS

Newer definitions outperformed Bell's staging using both standard statistics and most machine learning classifiers. The decision tree classifier had the highest overall machine learning scores, which resulted in Non-Bell definitions having high sensitivity (0.826, INC) and specificity (0.969, ST), while Modified Bell (IIA+) had reasonable sensitivity (0.783), but poor specificity (0.531). Feature importance evaluation identified nine criteria as important for diagnosis.

CONCLUSIONS

This preliminary study suggests that Non-Bell NEC definitions may be better at diagnosing NEC and calls for further examination of definitions and important criteria.

IMPACT

This article is the first formal head-to-head evaluation of current available definitions of NEC. Non-Bell NEC definitions may be more effective in identifying NEC based on findings from traditional measures of diagnostic performance and machine learning techniques. Nine features were identified as important for diagnosis from the definitions evaluated within the decision tree when performing supervised classification machine learning. This article serves as a preliminary study to formally evaluate the definitions of NEC utilized and should be expounded upon with a larger and more diverse patient cohort.

A protocol for the induction of experimental necrotizing enterocolitis in neonatal mice

Recapitulating human NEC using animal models has been insightful in dissecting the signaling pathways, immune-mediated mechanisms, genetic signatures, and the intestinal architecture of NEC. This protocol describes an in vivo murine NEC model, using hypoxia and formula containing lipopolysaccharide and enteric bacteria derived from an infant with NEC. With this mouse model, we aim to further dissect NEC pathogenesis and develop new therapeutic strategies.

For complete details on the use and execution of this protocol, please refer to Mihi et al. (2021).

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This protocol describes the induction of murine necrotizing enterocolitis (NEC)

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This mouse model is based on the use of hypoxia and formula supplemented with LPS

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This mouse model can be used to study NEC pathogenesis and therapeutic targets

Newborns with Bloody Stools-At the Crossroad between Efficient Management of Necrotizing Enterocolitis and Antibiotic Stewardship

The onset of bloody stools in neonates often results in antibiotic treatment for suspected necrotizing enterocolitis (NEC). Food protein-induced allergic proctocolitis (FPIAP) is an often-neglected differential diagnosis. We performed a retrospective analysis of antibiotic exposure at our tertiary center from 2011 to 2020 that included three time periods of differing antimicrobial stewardship goals. We compared these data with the conventional treatment guidelines (modified Bell's criteria). In our cohort of 102 neonates with bloody stools, the length of antibiotic exposure was significantly reduced from a median of 4 to 2 days. The proportion of treated neonates decreased from 100% to 55% without an increase in negative outcomes. There were 434 antibiotic days. Following a management strategy according to modified Bell's criteria would have led to at least 780 antibiotic days. The delayed initiation of antibiotic treatment was observed in 7 of 102 cases (6.9%). No proven NEC case was missed. Mortality was 3.9%. In conclusion, with FPIAP as a differential diagnosis of NEC, an observational management strategy in neonates with bloody stools that present in a good clinical condition seems to be justified. This may lead to a significant reduction of antibiotic exposure. Further prospective, randomized trials are needed to prove the safety of this observational approach.

Clinical Characteristics and Outcomes Until 2 Years of Age in Preterm Infants With Typical Chest Imaging Findings of Bronchopulmonary Dysplasia: A Propensity Score Analysis

Objective: The goal of the current study was to assess the associations of typical chest imaging findings of bronchopulmonary dysplasia (BPD) in preterm infants with clinical characteristics and outcomes until 2 years of age. Method: This retrospective cohort study enrolled 256 preterm infants with BPD who were admitted between 2014 and 2018. A propensity score analysis was used to adjust for confounding factors. The primary outcomes were the severity of BPD, home oxygen therapy (HOT) at discharge and mortality between 28 days after birth and 2 years of age. A multivariate logistic regression analysis was performed to identify related variables of mortality. Results: Seventy-eight patients with typical chest imaging findings were enrolled, of which 50 (64.1%) were first found by CXR, while 28 (35.9%) were first found by CT. In addition, 85.9% (67/78) were discovered before 36 weeks postmenstrual age (PMA) (gestational age [GA] < 32 weeks) or before 56 days after birth (GA > 32 weeks). After propensity score matching, the matched groups consisted of 58 pairs of patients. Those with typical imaging findings had a remarkably higher mortality rate (29.3 vs. 12.1%, p = 0.022, OR 3.021), higher proportion of severe BPD (32.8 vs. 12.1%, p = 0.003, OR 4.669) and higher rate of HOT at discharge (74.1 vs. 46.6%, p = 0.002, OR 3.291) than those without typical imaging findings. The multivariate logistic regression analysis showed that typical imaging findings ≤ 7 days and typical typical imaging findings >7 days were independent risk factors for mortality in preterm infants with BPD (OR 7.794, p = 0.004; OR 4.533, p = 0.001). Conclusions: More attention should be given to chest imaging findings of BPD, especially in the early stage (within 7 days). Early recognition of the development of BPD helps early individualized treatment of BPD. Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT04163822.

Potential Prenatal Origins of Necrotizing Enterocolitis

Necrotizing enterocolitis is a serious and yet incompletely understood gastrointestinal disease of infancy that predominately impacts premature neonates. Prevention is a key strategy for the management of necrotizing enterocolitis. Although postnatal risk factors have been the focus of prevention efforts, obstetric complications, including intrauterine inflammation and infection, growth restriction, preeclampsia, and prenatal medications, have been associated with an increased risk of necrotizing enterocolitis. This article reviews the evidence behind the prenatal risk factors for necrotizing enterocolitis, and discusses how these risk factors may elucidate the pathogenesis of necrotizing enterocolitis and provide insight into prevention and treatment.