Necrotizing enterocolitis comes in different forms: Historical perspectives and defining the disease

The conundrum of intestinal injury in preterm infants receiving mother's own milk

"Necrotizing enterocolitis" ("NEC") is a heterogeneous group of intestinal injuries experienced primarily in preterm infants. Risk factors include among others preterm gut microbiome alterations. Maternal milk (MM), or otherwise parent milk, is protective for the developing intestine due to its constituents, which include bioactive antimicrobials, immunomodulatory molecules, human milk oligosaccharides (HMOs), secretory immunoglobulin A (sIgA), and microorganisms. However, some preterm infants receiving exclusively mother's own milk (MOM) develop intestinal injuries. Studies showed predisposition to increased risk for "NEC", when a decreased MM HMO, disialyllacto-N-tetraose, is combined with an altered infant's gut microbiome. The intestine may also become more prone to injury with a greater amount of bacteria not bound to IgA. Variations in MM composition may alter the offspring gut microbiome, depriving protection. The different "NEC" entities should be considered to play a role as to why, in many studies, MOM does not provide absolute protection against preterm intestinal injury.

Placental abruption and the risk of necrotizing enterocolitis in neonates with birth weight ≥1500 grams; US national database study

BACKGROUND

The pathogenesis of necrotizing enterocolitis (NEC) is multifactorial, placental abruption is associated with serious neonatal complications attributed to disruption of the maternal-fetal vascular interface. This study aimed to investigate the association between placental abruption and NEC.

METHODS

We analyzed the United States (US) National Inpatient Sample (NIS) dataset for the years 2016-2018. Using the logistic regression model, the adjusted odds ratios (aOR) were calculated to assess the risk of NEC in infants born to mothers with placental abruption after controlling for significant confounders. Analyses were repeated after stratifying the population into two birth weight (BW) categories: <1500 g and ≥1500 g.

RESULTS

The study included 11,597,756 newborns. Placental abruption occurred in 0.16% of the population. NEC was diagnosed in 0.18% of infants, with a higher incidence (2.5%) in those born to mothers with placental abruption (aOR = 1.2, 95% CI: 1.1-1.3, p < 0.001). Placental abruption was associated with NEC only in infants with BW ≥ 1500 g (aOR = 1.34, 95% CI: 1.11-1.62, p 0.003).

CONCLUSION

Placental abruption is associated with an increased risk of NEC in neonates with BW ≥ 1500 g. Research is needed to explore the mechanisms behind this association and to develop targeted interventions to mitigate NEC risks in this population.

IMPACT

Placental abruption is associated with an increased risk of developing necrotizing enterocolitis (NEC) in neonates with a birth weight ≥1500 grams. This effect could be via direct in utero bowel injury or due to indirect postnatal compromise that occurs in these infants. This is the first study to specifically address the association between placental abruption and NEC in neonates ≥1500 g. The study used a national dataset that included all neonates delivered in the US, thereby allowing for the generalization of the findings after adjustment for multiple confounding factors. This study lays the groundwork for subsequent studies aimed at modifying feeding strategies and other neonatal management for the prevention of NEC in infants delivered after placental abruption.

Clinical Characteristics of Necrotizing Enterocolitis Diagnosed by Independent Adjudication of Abdominal Radiographs, Laparotomy, or Autopsy in Preterm Infants in the "Connection Trial"

OBJECTIVE

 Necrotizing enterocolitis (NEC) classically is diagnosed by radiographic demonstration of pneumatosis intestinalis/portal venous gas (PI/PVG). This study examines clinical characteristics of NEC confirmed by independent evaluation of abdominal radiographs, taken for clinical signs of NEC, or by pathologic findings at laparotomy or autopsy (confirmed NEC [cNEC]).

STUDY DESIGN

 The investigated cohort included 1,382 extremely low birth weight (BW) infants (BW range: 500-1,000 g) with median 27 weeks (range: 23-32) gestational age (GA) at birth. They were randomized into the placebo-controlled "Connection Trial" of the new biological drug candidate IBP-9414 with cNEC as one primary endpoint.

RESULTS

 Total 119 infants (8.6%) had cNEC diagnosed at median 14 days of age by confirming PI/PVG at X-ray adjudication (n = 111) and/or by surgery/autopsy (n = 21). Sixteen percent of cNEC cases died. Adverse events of NEC were reported in 8.5% of infants and 4.1% had NEC diagnosed by radiology and surgery/autopsy at the participating centers. Regression analyses showed that the risk of cNEC decreased by 11 to 30% for every 100-g increment in BW and single-week increment in GA and associated cNEC with odds ratios (ORs) > 2.0 for gastrointestinal (GI) perforation and obstruction, hypotension, hypokalemia, hypophosphatemia, and death. Comparing risks of cNEC in infants below and above 750-g BW showed higher ORs (2.7-4.3) for GI perforation, hypotension, hypokalemia, and renal complications in the smaller infants, whereas the bigger infants had higher ORs (1.9-3.2) for serious non-GI events, late-onset sepsis (LOS), and death. Predictors of cNEC (hazard ratio, HR > 1.5) included serious non-GI events (mainly infections), hyponatremia, and hyperglycemia, whereas the HR was 0.52 for intravenous antibiotics. After cNEC diagnosis, there were higher rates of GI perforation and obstruction, hypotension, hypokalemia, and LOS.

CONCLUSION

 Independent adjudication of abdominal radiographs increased radiological recognition of NEC and proved to be feasible in a multicenter study setting as well as able to diagnose clinically relevant NEC.

KEY POINTS

· Independent adjudication of abdominal radiographs in ELBW infants increased NEC recognition.. · Risk of NEC decreased by 11 to 30% with every 100-g increment in BW and GA week.. · In infants with BW 750 to 1,000 g, the risk of death from NEC was almost twice that in infants with BW 500 to 749 g. · Infants with NEC received antibiotics during one-third and parenteral nutrition during half of the first 7 postnatal weeks..

Reassessing acquired neonatal intestinal diseases using unsupervised machine learning

BACKGROUND

Acquired neonatal intestinal diseases have an array of overlapping presentations and are often labeled under the dichotomous classification of necrotizing enterocolitis (which is poorly defined) or spontaneous intestinal perforation, hindering more precise diagnosis and research. The objective of this study was to take a fresh look at neonatal intestinal disease classification using unsupervised machine learning.

METHODS

Patients admitted to the University of Florida Shands Neonatal Intensive Care Unit January 2013-September 2019 diagnosed with an intestinal injury, or had imaging findings of portal venous gas, pneumatosis, abdominal free air, or had an abdominal drain placed or exploratory laparotomy during admission were included. Congenital gastroschisis, omphalocele, intestinal atresia, malrotation were excluded. Data was collected via retrospective chart review with subsequent hierarchal, unsupervised clustering analysis.

RESULTS

Five clusters of intestinal injury were identified: Cluster 1 deemed the "Low Mortality" cluster, Cluster 2 deemed the "Mature with Inflammation" cluster, Cluster 3 deemed the "Immature with High Mortality" cluster, Cluster 4 deemed the "Late Injury at Full Feeds" cluster, and Cluster 5 deemed the "Late Injury with High Rate of Intestinal Necrosis" cluster.

CONCLUSION

Unsupervised machine learning can be used to cluster acquired neonatal intestinal injuries. Future study with larger multicenter datasets is needed to further refine and classify types of intestinal diseases.

IMPACT

Unsupervised machine learning can be used to cluster types of acquired neonatal intestinal injury. Five major clusters of acquired neonatal intestinal injury are described, each with unique features. The clusters herein described deserve future, multicenter study to determine more specific early biomarkers and tailored therapeutic interventions to improve outcomes of often devastating neonatal acquired intestinal injuries.

A Quality Improvement Initiative to Reduce Necrotizing Enterocolitis in Very Preterm Infants

OBJECTIVE

To reduce the incidence of necrotizing enterocolitis (NEC) among very preterm infants in the Calgary Health Region to ≤2% within 2 years.

METHODS

A multidisciplinary team developed key drivers for NEC. Targeted interventions included strategies to increase mothers' own milk (MOM), improve compliance with feeding regimens, standardize management of feeding intolerance, prevent intestinal microbial aberrations, and feed conservatively during blood transfusion and the treatment of patent ductus arteriosus. The outcome measure was NEC (≥ stage 2). Changes in NEC rates were examined among racial and ethnic groups. Process measures included MOM feeding at discharge, the difference between actual and expected time to reach full feeds, lowest hemoglobin, and the duration of empirical antibiotics. Growth, the rate of blood transfusion, and the duration of parenteral nutrition were balancing measures. The preintervention, intervention, and sustainment periods were January 2013 to June 2016, July 2016 to December 2018, and December 2018 to December 2021, respectively.

RESULTS

We included 2787 infants born at ≤326/7 weeks' gestation (1105 preintervention, 763 during intervention, and 919 in sustainment). NEC decreased from 5.6% to 1.9%. Process measures indicated increased MOM feeding at discharge, improved compliance with feeding regimens, increased lowest hemoglobin levels, and shorter durations of empirical antibiotics. Balancing measures revealed improved weight Z-scores, shorter durations on parenteral nutrition, and increased rates of blood transfusion.

CONCLUSIONS

Quality improvement initiatives to increase MOM, improve compliance with feeding regimens, feed conservatively during blood transfusion and treatment of patent ductus arteriosus, and prevent intestinal microbial aberrations were associated with reduced NEC.

The validity of hospital diagnostic and procedure codes reflecting morbidity in preterm neonates born <32 weeks gestation

OBJECTIVE

To determine the validity of diagnostic hospital billing codes for complications of prematurity in neonates <32 weeks gestation.

STUDY DESIGN

Retrospective cohort data from discharge summaries and clinical notes (n = 160) were reviewed by trained, blinded abstractors for the presence of intraventricular hemorrhage (IVH) grades 3 or 4, periventricular leukomalacia (PVL), necrotizing enterocolitis (NEC), stage 3 or higher, retinopathy of prematurity (ROP), and surgery for NEC or ROP. Data were compared to diagnostic billing codes from the neonatal electronic health record.

RESULTS

IVH, PVL, ROP and ROP surgery had strong positive predictive values (PPV > 75%) and excellent negative predictive values (NPV > 95%). The PPVs for NEC (66.7%) and NEC surgery (37.1%) were low.

CONCLUSION

Diagnostic hospital billing codes were observed to be a valid metric to evaluate preterm neonatal morbidities and surgeries except in the instance of more ambiguous diagnoses such as NEC and NEC surgery.

Identification of serum biomarkers for necrotizing enterocolitis using aptamer-based proteomics

Introduction

Necrotizing enterocolitis (NEC) is a potentially fatal intestinal disease primarily affecting preterm infants. Early diagnosis of neonates with NEC is crucial to improving outcomes; however, traditional diagnostic tools remain inadequate. Biomarkers represent an opportunity to improve the speed and accuracy of diagnosis, but they are not routinely used in clinical practice.

Methods

In this study, we utilized an aptamer-based proteomic discovery assay to identify new serum biomarkers of NEC. We compared levels of serum proteins in neonates with and without NEC and identified ten differentially expressed serum proteins between these groups.

Results

We detected two proteins, C-C motif chemokine ligand 16 (CCL16) and immunoglobulin heavy constant alpha 1 and 2 heterodimer (IGHA1 IGHA2), that were significantly increased during NEC and eight that were significantly decreased. Generation of receiver operating characteristic (ROC) curves revealed that alpha-fetoprotein (AUC = 0.926), glucagon (AUC = 0.860), and IGHA1 IGHA2 (AUC = 0.826) were the proteins that best differentiated patients with and without NEC.

Discussion

These findings indicate that further investigation into these serum proteins as a biomarker for NEC is warranted. In the future, laboratory tests incorporating these differentially expressed proteins may improve the ability of clinicians to diagnose infants with NEC rapidly and accurately.

The role of neutrophil extracellular traps in necrotizing enterocolitis

Necrotizing enterocolitis (NEC) continues to be one of the most common causes of mortality and morbidity in preterm infants. Although not fully elucidated, studies suggest that prematurity, formula feeding, imbalanced vascular supply, and altered bacterial colonization play major roles in the pathogenesis of NEC. NEC is characterized by increased cytokine release and leukocyte infiltration. Recent data from preterm infants and animal models of NEC suggest that neutrophil extracellular traps (NETs) are released in intestinal tissue. The contribution of NETs in the pathogenesis and/or prevention/treatment of this disease continues to be controversial. Here, we review the available data on NETs release in NEC in human patients and in different NEC models, highlighting their potential contribution to pathology and resolution of inflammation. Here, we review the available data on NETs release in NEC in human patients and the different NEC models, highlighting their potential contribution to pathology or resolution of inflammation.

Probiotics to prevent necrotizing enterocolitis in very low birth weight infants: A network meta-analysis

Objective

This study aims to review the evidence for the optimal regimen of probiotics for the prevention of necrotizing enterocolitis (NEC) in very low birth weight infants.

Design

Through searching PubMed, EMBASE, Cochrane Library, and Web of Science till September 30, 2022, only randomized controlled trials were included to evaluate the optimal regimen of probiotics for the prevention of NEC in very low birth weight infants. The methodological quality of the included studies was assessed by the Cochrane risk of bias assessment tool (RoB 2), and the collected data were analyzed accordingly using Stata software.

Results

Twenty-seven RCTs were included, and the total sample size used in the study was 529. The results of the network meta-analysis showed that Bovine lactoferrin + Lactobacillus rhamnosus GG (RR 0.03; 95% CI 0.00-0.35), Lactobacillus rhamnosus + Lactobacillus plantarum + Lactobacillus casei + Bifidobacterium lactis (RR 0.06; 95% CI 0.00-0.70), Bifidobacterium lactis + inulin (RR 0.16; 95% CI 0.03-0.91) were superior to the control group (Bifidobacterium lactis + Bifidobacterium longum) in reducing the incidence of NEC. The reduction in the incidence of NEC were as follows: Bovine lactoferrin + Lactobacillus rhamnosus GG (SUCRA 95.7%) > Lactobacillus rhamnosus + Lactobacillus plantarum + Lactobacillus casei + Bifidobacterium lactis (SUCRA 89.4%) > Bifidobacterium lactis + inulin (SUCRA 77.8%).

Conclusions

This network meta-analysis suggests that Lactobacillus rhamnosus GG combined with bovine lactoferrin maybe the most recommended regimen for the prevention of NEC in very low birth weight infants.

Multiomics, artificial intelligence, and precision medicine in perinatology

Technological advances in omics evaluation, bioinformatics, and artificial intelligence have made us rethink ways to improve patient outcomes. Collective quantification and characterization of biological data including genomics, epigenomics, metabolomics, and proteomics is now feasible at low cost with rapid turnover. Significant advances in the integration methods of these multiomics data sets by machine learning promise us a holistic view of disease pathogenesis and yield biomarkers for disease diagnosis and prognosis. Using machine learning tools and algorithms, it is possible to integrate multiomics data with clinical information to develop predictive models that identify risk before the condition is clinically apparent, thus facilitating early interventions to improve the health trajectories of the patients. In this review, we intend to update the readers on the recent developments related to the use of artificial intelligence in integrating multiomic and clinical data sets in the field of perinatology, focusing on neonatal intensive care and the opportunities for precision medicine. We intend to briefly discuss the potential negative societal and ethical consequences of using artificial intelligence in healthcare. We are poised for a new era in medicine where computational analysis of biological and clinical data sets will make precision medicine a reality. IMPACT: Biotechnological advances have made multiomic evaluations feasible and integration of multiomics data may provide a holistic view of disease pathophysiology. Artificial Intelligence and machine learning tools are being increasingly used in healthcare for diagnosis, prognostication, and outcome predictions. Leveraging artificial intelligence and machine learning tools for integration of multiomics and clinical data will pave the way for precision medicine in perinatology.

Current and future methods of probiotic therapy for necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a complex intestinal disease that primarily affects premature neonates. Given its significant mortality and morbidity, there is an urgent need to develop improved prophylactic measures against the disease. One potential preventative strategy for NEC is the use of probiotics. Although there has been significant interest for decades in probiotics in neonatal care, no clear guidelines exist regarding which probiotic to use or for which patients, and no FDA-approved products exist on the market for NEC. In addition, there is lack of agreement regarding the benefits of probiotics in neonates, as well as some concerns about the safety and efficacy of available products. We discuss currently available probiotics as well as next-generation probiotics and novel delivery strategies which may offer an avenue to capitalize on the benefits of probiotics, while minimizing the risks. Thus, probiotics may still prove to be an effective prevention strategy for NEC, although further product development and research is needed to support use in the preterm population.

Causes of bloody stools in neonates: a case series report

BACKGROUND

Bloody stools in a neonate may stand for a spectrum of conditions ranging from benign to life-threatening. It is critical to detect the cases that have significant underlying pathology, especially those which require urgent surgical intervention. Previous studies always focused on one particular disease related to bloody stools in neonates, or the study only involved a small number of cases. This study aimed to investigate the common causes of bloody stools in neonates.

METHODS

This retrospective cohort study included the neonates admitted to our institution due to "bloody stools" over a 5-year period. We compared the differences among patients' characteristics, feeding choice, underlying diseases, and operation rate between preterm and term neonates.

RESULTS

A total of 300 patients were included, accounting for 1.1% of the total neonatal admissions. The overall rate of exclusive breastfeeding was 28.0%. The most common underlying causes for bloody stools were: cow's milk protein allergy (CMPA, 53.3%), swallowed blood syndrome (10.0%), viral enteritis (9.7%), necrotizing enterocolitis (NEC) > stage II (8.3%), non-specific enteritis (7.3%), and anal fissure (5.0%). The median [interquartile range (IQR)] onset age for bloody stools for all infants was 12 [3-22] days after birth. Preterm neonates had a lower rate of exclusive breastfeeding (P=0.844), higher incidence of NEC > stage II (P=0.014), later bloody stools onset age (P<0.001), and longer length of hospital stay than term neonates (P<0.001). For neonates with NEC, those with bottle-fed had an earlier onset age for bloody stools than those with breast-fed (P=0.027). Only 1.7% (n=5) required surgery (2 stage III NEC, 1 post-NEC stricture, and 2 volvuli). Survival at hospital discharge was 100%.

CONCLUSIONS

Bloody stools in neonates is generally a benign, self-limiting disorder, not related to surgical conditions. The overall operation rate among neonates with bloody stools was only 1.7%. CMPA and NEC were the most common underlying non-surgical and surgical diseases, respectively, for neonates with bloody stools. Feeding choice is related to bloody stools in neonates, policies and strategies to support breastfeeding should be strengthened in the future.

Effect of Maternal Diet on Any Necrotizing Enterocolitis in Neonates: A Randomized Double-Blind Study

Background: The etiology of necrotizing enterocolitis (NEC) is controversially discussed. One of the most recently proposed causes of NEC is an allergy to cow's milk protein. This study was designed to evaluate the effect of a maternal diet without bovine protein on the incidence of any NEC in very low birth weight (VLBW) infants. Materials and Methods: A pilot randomized controlled clinical trial was performed at Akbarabadi Hospital, Tehran, Iran, from December 2019 to July 2020, in women with VLBW infants. One hundred twenty mothers with VLBW neonates were randomly assigned to the intervention or the control group (60 in each). In the intervention group, mothers were given a dairy-free diet during the first 14 days after the newborn's onset of feeding. No special diet was given to the control group. The primary outcome of the study was the rate of any NEC in neonates, which was compared between groups. Any NEC was defined as Bell stage I or greater. Results: The minimum and maximum gestational ages were 26 and 33 weeks, respectively. The minimum birth weight of neonates was 700 g. The two groups did not differ significantly in terms of demographic and preinterventional clinical characteristics. Any NEC was reported in 0% and 10% (5/52) of neonates in the intervention and control groups, respectively; the difference was statistically significant (p = 0.028). The NEC symptoms began ∼34 days after birth. Four cases of NEC were classified as Bell stage I, and one was classified as Bell stage II. No statistical association was registered between sex, gestational age, birth weight, and the onset of feeding with the incidence of any NEC. Conclusion: The use of a cow's milk protein-free diet in mothers and exclusive breastfeeding in preterm VLBW infants may reduce the incidence of NEC. We recommend further studies with larger sample sizes in a multicenter setting. The study was registered at the Iranian Registry of Clinical Trials (IRCT20200415047086N1).

Fecal amine metabolite analysis before onset of severe necrotizing enterocolitis in preterm infants: a prospective case-control study

Infants developing necrotizing enterocolitis (NEC) have a different metabolomic profile compared to controls. The potential of specific metabolomics, i.e. amino acids and amino alcohols (AAA), as early diagnostic biomarkers for NEC is largely unexplored. In this multicenter prospective case-control study, longitudinally collected fecal samples from preterm infants (born <30 weeks of gestation) from 1-3 days before diagnosis of severe NEC (Bell's stage IIIA/IIIB), were analyzed by targeted high-performance liquid chromatography (HPLC). Control samples were collected from gestational and postnatal age-matched infants. Thirty-one NEC cases (15 NEC IIIA;16 NEC IIIB) with 1:1 matched controls were included. Preclinical samples of infants with NEC were characterized by five increased essential amino acids-isoleucine, leucine, methionine, phenylalanine and valine. Lysine and ethanolamine ratios were lower prior to NEC, compared to control samples. A multivariate model was rendered based on isoleucine, lysine, ethanolamine, tryptophan and ornithine, modestly discriminating cases from controls (AUC 0.67; p < 0.001). Targeted HPLC pointed to several specific AAA alterations in samples collected 1-3 days before NEC onset, compared to controls. Whether this reflects metabolic alterations and has a role in early biomarker development for NEC, has yet to be elucidated.

Intestinal Resection is More Likely to be Effective in Necrotizing Enterocolitis Extending to Colon than in Disease Limited to the Small Intestine

Background:

The prognosis in surgical necrotizing enterocolitis (NEC) has focused on the total length of the resected bowel; the relative impact of small intestinal vs colonic resection is not well studied.

Objective:

We hypothesized that intestinal resections may reduce mortality and length of hospital stay (LOS) more likely in infants who have NEC extending into the colon than in those with disease limited to the small intestine. We also investigated the relationship between gestational maturation and NEC-related mortality.

Methods:

A retrospective study of 153 patients compared demographic, clinical, and histopathological information in infants who had NEC limited to the small intestine vs disease with colonic involvement.

Results:

Our 153 infants had a mean (±standard deviation) gestational age of 27.4 ± 3.4 weeks and a birth weight of 987 ± 505 g. NEC was limited to the small intestine in 103 (67.3%) infants and extended into the colon in 50 (32.7%). Infants with small intestinal NEC needed shorter bowel resections of 28 ± 31.9 cm than 42.2 ± 40.7 cm in those with colonic involvement (p = 0.02). The LOS was longer in NEC limited to the small intestine than in disease with colonic lesions (96 ± 88.1 vs 69.7 ± 19.1 days; p <0.05). In small intestinal NEC, mortality decreased to <50% beyond a gestational age (GA) >37 weeks. In contrast, infants with NEC that involved the colon had mortality <50% mortality beyond 27.3 weeks’ GA (p = 0.008).

Conclusions:

Bowel resections may be more likely associated with shorter LOS in surgical NEC that involves both the small bowel and colon, even when longer segments of the gastrointestinal tract are removed, than in disease limited to the small intestine.

Prevention of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is considered to be one of the most devastating intestinal diseases seen in neonatal intensive care. Measures to treat NEC are often too late, and we need effective preventative measures to alleviate the burden of this disease. The purpose of this review is to summarize currently used measures, and those showing future promise for prevention.

Using machine learning analysis to assist in differentiating between necrotizing enterocolitis and spontaneous intestinal perforation: A novel predictive analytic tool

PURPOSE

Necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP) are devastating diseases in preterm neonates, often requiring surgical treatment. Previous studies evaluated outcomes in peritoneal drain placement versus laparotomy, but the accuracy of the presumptive diagnosis remains unknown without bowel visualization. Predictive analytics provide the opportunity to determine the etiology of perforation and guide surgical decision making. The purpose of this investigation was to build and evaluate machine learning models to differentiate NEC and SIP.

METHODS

Neonates who underwent drain placement or laparotomy NEC or SIP were identified and grouped definitively via bowel visualization. Patient characteristics were analyzed using machine learning methodologies, which were optimized through areas under the receiver operating characteristic curve (AUROC). The model was further evaluated using a validation cohort.

RESULTS

40 patients were identified. A random forest model achieved 98% AUROC while a ridge logistic regression model reached 92% AUROC in differentiating diseases. When applying the trained random forest model to the validation cohort, outcomes were correctly predicted.

CONCLUSIONS

This study supports the feasibility of using a novel machine learning model to differentiate between NEC and SIP prior to any intended surgical interventions.

LEVEL OF EVIDENCE

level II TYPE OF STUDY: Clinical Research Paper.

Enteral Feeding Interventions in the Prevention of Necrotizing Enterocolitis: A Systematic Review of Experimental and Clinical Studies

Necrotizing enterocolitis (NEC), which is characterized by severe intestinal inflammation and in advanced stages necrosis, is a gastrointestinal emergency in the neonate with high mortality and morbidity. Despite advancing medical care, effective prevention strategies remain sparse. Factors contributing to the complex pathogenesis of NEC include immaturity of the intestinal immune defense, barrier function, motility and local circulatory regulation and abnormal microbial colonization. Interestingly, enteral feeding is regarded as an important modifiable factor influencing NEC pathogenesis. Moreover, breast milk, which forms the currently most effective prevention strategy, contains many bioactive components that are known to support neonatal immune development and promote healthy gut colonization. This systematic review describes the effect of different enteral feeding interventions on the prevention of NEC incidence and severity and the effect on pathophysiological mechanisms of NEC, in both experimental NEC models and clinical NEC. Besides, pathophysiological mechanisms involved in human NEC development are briefly described to give context for the findings of altered pathophysiological mechanisms of NEC by enteral feeding interventions.

Clinical determinants of postoperative outcomes in surgical necrotizing enterocolitis

OBJECTIVE

Investigate predictors of postoperative morbidity and mortality in surgical NEC.

STUDY DESIGN

We analyzed the clinical outcomes of infants with surgical NEC from the years 2000-2015.

RESULTS

Ninety infants born at gestation (mean ± standard deviation, SD; standard error of mean, SEM) 27.3 ± 6.6 weeks (SEM ± 0.07 weeks) and weighing 1008 ± 456 g (SEM ± 48 g) developed NEC on 25.2 ± 22.4 days (SEM ± 2.4 days). Average bowel resection was 29.2 ± 30.5 cm (SEM ± 3.2 cm). Postoperative Ileus lasted 16.5 ± 12.2 days (SEM ± 1.3 days), and was significantly longer in infants with higher gestation and birth weight, age at onset of NEC, length of intestinal resection, maternal chorioamnionitis, and need for pressors. Thirty-eight (42.2%) infants died. Mortality was higher at gestation <31 weeks.

CONCLUSION

Gestational age, birth weight, age at NEC onset, and length of resected bowel determined postoperative morbidity and mortality in NEC. Length of hospital stay was affected by above factors, and also the duration of postoperative ileus and parenteral nutrition.

Congenital Diarrheal Diseases

Early diagnosis of diarrhea is critical to prevent disease progression. Diarrhea in newborns can be congenital or acquired; acquired diarrheas are the major cause in infants. Congenital diarrheal diseases are rare and include defects in digestion, absorption, and transport of nutrients, and electrolytes; disorders of enterocyte differentiation and polarization; defects of enteroendocrine cell differentiation; dysregulation of the intestinal immune response; and dysfunction of the immune system. This review discusses the clinical approach that may help in early identification and management of different congenital diarrheal diseases.

Gut Injury and the Microbiome in Neonates

The causes of neonatal gut injury are multifactorial and include ischemia, tissue hypoxia due to anemia, excessive inflammation, deficiency of growth factors, and food protein sensitivity. The developing intestinal microbiome plays a role in some of these forms of intestinal injury but knowledge of its relative role in each remains poorly understood. Commensal bacteria are required for normal immune development and immune tolerance. Dysbiosis in the neonatal gut that alters the patterns of commensal and pathogenic bacteria may accentuate gut injury.

Hypoxic-ischemic enterocolitis: a proposal of a new terminology for early NEC or NEC-like disease in preterm infants, a single-center prospective observational study

We aimed to investigate the role of hypoxia-ischemia in the pathophysiology of early NEC/NEC like disease (ENEC) and classic NEC/NEC like disease (CNEC) in preterm infants. In this pilot study, preterm infants who developed the clinical symptoms and signs of NEC/NEC like disease were divided into two groups as early (≤ 7 days, ENEC) or late (> 7 days, CNEC) groups. Beside clinical variables, serum L-lactate, endothelin-1 (ET-1), platelet activating factor (PAF), and intestinal fatty acid binding protein (I-FABP) levels were measured from umbilical/peripheric venous blood in the first hour of life and during the clinical presentation in all groups. A total of 86 preterm infants were enrolled in the study. In the ENEC group, the incidences of fetal umbilical artery Doppler velocimetry abnormalities, IUGR, and delayed passage of first meconium were higher. In addition, mean levels of L-lactate, ET-1, PAF, and I-FABP were higher in the first hour of life.Conclusion: Our study firstly showed that the dominant pathophysiological factor of ENEC is prenatal hypoxic-ischemic event where intestinal injury and inflammation begin in-utero and become clinically apparent in the first week of life. Therefore, we propose a new term "Hypoxic-Ischemic Enterocolitis (HIEnt)" for the definition of ENEC in preterm infants with prenatal hemodynamic disturbances and IUGR. This new sight can provide individualized preventive and therapeutic strategies for preterm infants.What is Known:• The pathophysiology of early necrotizing enterocolitis (NEC) or NEC-like disease which is seen in the first week of life seems different than classic necrotizing enterocolitis (CNEC) which is always seen after the first week of life.What is New:• This study suggests that perinatal hypoxic-ischemic process with inflammation is the point of origin of fetal intestinal injury leading to ENEC.• We propose a new term "Hypoxic-Ischemic Enterocolitis (HIEnt)" for the definition and differentiation of this unique clinical entity.

Preterm neonatal immunology at the intestinal interface

Fetal and neonatal development represents a critical window for setting a path toward health throughout life. In this review, we focus on intestinal immunity, how it develops, and its implications for subsequent neonatal diseases. We discuss maternal nutritional and environmental exposures that dictate outcomes for the developing fetus. Although still controversial, there is evidence in support of an in utero microbiome. Specific well-intentioned and routine applications of antibiotics, steroids, and surgical interventions implemented before, during, and after birth skew the neonate towards pro-inflammatory dysbiosis. Shortly after birth, a consortium of maternal and environmentally derived bacteria, through cross-talk with the developing host immune system, takes center stage in developing or disrupting immune homeostasis at the intestinal interface. We also examine subsequent immunological cross-talks, which involve neonatal myeloid and lymphoid responses, and their potential impacts on health and disease such as necrotizing enterocolitis and sepsis, especially critical disease entities for the infant born preterm.

Necrotizing Enterocolitis: A Multi-omic Approach and the Role of the Microbiome

Necrotizing enterocolitis (NEC) is a poorly defined disease that primarily affects preterm infants. There has not been much progress in the prevention or treatment of NEC since it became recognized as a common problem in preterm infants. Reasons for this lack of progress include the likelihood that different diseases are being put under the same moniker of "NEC," similar to using "diabetes" for the different diseases it represents. In order to make progress, better delineation of the phenotypes that present as NEC will be necessary to clearly establish their pathophysiology, find specific and sensitive biomarkers, and establish preventative regimens. In this review, we summarize some of the entities that are being called NEC, discuss the pathophysiology of the most classic form of NEC, and provide an overview of how we might proceed in the future to make progress in this field.

Emerging Biomarkers for Prediction and Early Diagnosis of Necrotizing Enterocolitis in the Era of Metabolomics and Proteomics

Necrotizing Enterocolitis (NEC) is a catastrophic disease affecting predominantly premature infants and is characterized by high mortality and serious long-term consequences. Traditionally, diagnosis of NEC is based on clinical and radiological findings, which, however, are non-specific for NEC, thus confusing differential diagnosis of other conditions such as neonatal sepsis and spontaneous intestinal perforation. In addition, by the time clinical and radiological findings become apparent, NEC has already progressed to an advanced stage. During the last three decades, a lot of research has focused on the discovery of biomarkers, which could accurately predict and make an early diagnosis of NEC. Biomarkers used thus far in clinical practice include acute phase proteins, inflammation mediators, and molecules involved in the immune response. However, none has been proven accurate enough to predict and make an early diagnosis of NEC or discriminate clinical from surgical NEC or other non-NEC gastrointestinal diseases. Complexity of mechanisms involved in NEC pathogenesis, which remains largely poorly elucidated, could partly explain the unsatisfactory diagnostic performance of the existing NEC biomarkers. More recently applied technics can provide important insight into the pathophysiological mechanisms underlying NEC but can also aid the detection of potentially predictive, early diagnostic, and prognostic biomarkers. Progress in omics technology has allowed for the simultaneous measurement of a large number of proteins, metabolic products, lipids, and genes, using serum/plasma, urine, feces, tissues, and other biological specimens. This review is an update of current data on emerging NEC biomarkers detected using proteomics and metabolomics, further discussing limitations and future perspectives in prediction and early diagnosis of NEC.

Necrotizing Enterocolitis: The Future

Progress in our understanding of the pathophysiology, prevention and treatment of necrotizing enterocolitis (NEC) has been hampered for many reasons. Included among these is the fact that what we are calling "NEC" is likely to represent different disease processes, which need to be delineated before evaluating individual pathogenic mechanisms and attempting to develop predictive and diagnostic biomarkers. Treatment is also likely to be hampered because not all of the different entities called "NEC" will respond to the same regimen. In this review, some of these entities will be discussed in more detail, with suggestions for refining our approach toward improving methods for their diagnosis, prevention and treatment.

[Protective effect of Lactobacillus reuteri against oxidative stress in neonatal mice with necrotizing enterocolitis]

OBJECTIVE

To investigate the protective effect of L. reuteri DSM17938 strain against oxidative stress in a neonatal mouse model of necrotizing enterocolitis (NEC) and explore the possible mechanism.

METHODS

Ninety-six 10-day-old neonatal C57BL/6J mice were equally randomized into control group, NEC group, and NEC+ L. reuteri group. The pathological changes of the ileocecal intestinal tissue were evaluated with HE staining and double-blind pathological scoring. The mRNA and protein expressions of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the intestinal tissues were detected using quantitative real-time PCR and ELISA, respectively. Colorimetric assays were used to determine the activity of superoxide dismutase (SOD) and its inhibition rate, malondialdehyde (MDA), glutathione (GSH), oxidized glutathione (GSSG), and GSSG/ GSH ratio.

RESULTS

Compared with those in the control group, the neonatal mice in NEC group showed significant weight loss (P < 0.05), obvious intestinal injury, increased pathological scores (P < 0.05), increased expressions of TNF-α and IL-1β mRNA and proteins (P < 0.05), decreased SOD activity and inhibition rate, decreased GSH, and significantly increased MDA, GSSG, and GSSG/GSH ratios (P < 0.05). Treatment with L. reuteri obviously decreased the pathological scores, expressions of TNF-α and IL-1β (P < 0.05), MDA, GSSG, and GSSG/GSH ratio (P < 0.05), and significantly increased SOD activity, its inhibition rate, and GSH level in the mice with NEC, but the survival rate was not significantly different between NEC and L. reuteri-treated groups (P > 0.05).

CONCLUSIONS

L. reuteri DSM17938 can offer protection against NEC in mice by reducing oxidative stress and increasing antioxidant capacity of the intestinal tissue to suppress intestinal inflammations.

Abdominal ultrasound should become part of standard care for early diagnosis and management of necrotising enterocolitis: a narrative review

Necrotising enterocolitis (NEC) is a leading cause of death and disability in preterm newborns. Early diagnosis through non-invasive investigations is a crucial strategy that can significantly improve outcomes. Hence, this review gives particular attention to the emerging role of abdominal ultrasound (AUS) in the early diagnosis of NEC, its performance against abdominal radiograph and the benefits of AUS use in daily practice. AUS has been used in the diagnosis and management of NEC for a couple of decades. However, its first-line use has been minimal, despite growing evidence demonstrating AUS can be a critical tool in the early diagnosis and management of NEC. In 2018, the NEC group of the International Neonatal Consortium recommended using AUS to detect pneumatosis and/or portal air in preterm NEC as part of the 'Two out of three' model. To facilitate widespread adoption, and future improvement in practice and outcomes, collaboration between neonatologists, surgeons and radiologists is needed to generate standard operating procedures and indications for use for AUS. The pace and scale of the benefit generated by use of AUS can be amplified through use of computer-aided detection and artificial intelligence.

Multiomics-based strategies for taming intestinal inflammation in the neonate

PURPOSE OF REVIEW

The purpose of this review is to discuss evolving research into intestinal inflammatory responses as they relate to the developing microbiome and to provide insights into developing multiomic tools that are being used to describe these relationships. Intestinal inflammatory conditions are common, and in the neonate present special challenges, especially in the form of necrotizing enterocolitis (NEC) and other conditions that involve damage or breakdown of the mucosal barrier, leading to systemic inflammation and damage to distal sites, such as the liver and brain.

RECENT FINDINGS

Recent studies show that when a dysbiosis (microbial imbalance or impaired microbiota) occurs, an inflammatory response that can affect the entire body is frequently the result. We are recognizing that not only the microbial diversity and relative abundance of certain taxa play a role in dysbiosis and inflammation, but their functional capabilities in terms of metabolite production and interaction with the immune system of the host afre critical in future health and disease.

SUMMARY

A multiomic approach to evaluate these microorgansims as well as their interaction with the host by using systems-based concepts is becoming possible and is likely to shed new light on various disease entities and how we can best prevent and treat them.

Agreement between study designs: a systematic review comparing observational studies and randomized trials of surgical treatments for necrotizing enterocolitis

Background: It is unknown whether observational studies comparing laparotomy versus peritoneal drainage for surgical treatment of necrotizing enterocolitis (NEC) in preterm infants differ from randomized controlled trials (RCTs) of the same interventions. Further, in the absence of sufficient RCT evidence, it is uncertain how best to use existing observational data to guide clinical decision making.Methods: We performed a systematic review and meta-analysis of articles comparing laparotomy versus peritoneal drainage for preterm infants with NEC. Two authors independently searched PubMed and the Cochrane Database of Systematic Reviews, from 1 January 1990 to 1 May 2017 and selected articles that: (1) included low birthweight (<2500 g) or preterm (<37-week gestation) infants, (2) compared laparotomy versus peritoneal drainage for NEC, and (3) reported all-cause mortality (primary outcome) in both groups. The same two authors extracted data about study outcomes and about study quality, which was assessed using the Consolidated Standards of Reporting Trials (CONSORT) checklist for reporting of RCTs and Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist for reporting of observational studies. Random-effects meta-analysis was used to generate weighted odds ratios (OR).Results: Twenty-five observational studies and two RCTs met all eligibility criteria. Outcomes were reported for 16,288 patients: 16,103 from observational studies and 185 from RCTs. Meta-analysis of observational studies demonstrated significantly lower mortality after laparotomy, as compared to peritoneal drainage (pooled OR 0.54, 95% CI 0.34-0.84). In contrast, RCTs demonstrated no difference in mortality (pooled OR 0.85, 95% CI 0.47-1.54). In post hoc analyses, observational studies were separated into two subgroups: low versus high quality of reporting, based on the STROBE checklist. Observational studies with low quality of reporting significantly favored laparotomy (pooled OR 0.38, 95% CI 0.18-0.81). In contrast and similar to RCTs, observational studies with high quality of reporting showed no difference in mortality (pooled OR 0.67, 95% CI 0.37-1.19).Conclusions: Neither RCTs nor observational studies with high quality of reporting demonstrate differences in mortality when preterm infants with surgical NEC are managed with laparotomy or peritoneal drainage. While RCTs remain a gold standard for evaluation of therapies, results from high quality observational studies may approximate the results of RCTs and might guide clinical practice until adequate RCT evidence is available.