Necrotizing enterocolitis: A multifactorial disease with no cure

Gut microbiome and inflammation in response to increasing intermittent hypoxia in the neonatal rat

BACKGROUND

Intermittent hypoxia (IH) and oxidative stress play key roles in gut dysbiosis and inflammation. We tested the hypothesis that increasing numbers of daily IH episodes cause microbiome dysbiosis and severe gut injury.

METHODS

Neonatal rats were exposed to hyperoxia (Hx), growth restriction, and IH. For IH, pups were exposed to 2-12 daily episodes from birth (P0) to postnatal day 7 (7D) or P0-P14 (14D), with or without recovery in room air (RA) until P21. Animals raised in RA from P0 to P21 served as normoxia controls. Stool was expressed from the large intestines for microbiome analysis, and tissue samples were assessed for histopathology and biomarkers of inflammation.

RESULTS

Hx and IH caused a significant reduction in the number and diversity of organisms. The severity of gut injury and levels of inflammatory cytokines and TLR4 increased, while total glutathione (tGSH) declined, with increasing daily IH episodes. The number of organisms correlated with the villi number (p < 0.05) and tGSH depletion (p < 0.001).

CONCLUSIONS

The critical number of daily IH episodes that the newborn gut may sustain is 6, beyond which irreversible damage occurs. The immature gut is highly susceptible to IH-induced injury, and IH may contribute to pathological outcomes in the immature gut.

IMPACT STATEMENT

1. The neonatal gut at birth is highly susceptible to intermittent hypoxia (IH) injury. 2. IH causes gut dysbiosis, inflammation, and glutathione depletion. 3. The severity of gut injury worsens as a function of increasing daily IH episodes. 4. The critical number of daily IH episodes that the newborn gut may sustain is 6, beyond which irreversible damage occurs.

Necrotising enterocolitis in a middle-income country: Early onset and risk factors for mortality

AIM

There is limited literature available about necrotising enterocolitis (NEC) in low- and middle-income countries. This study sought to determine the proportion, pattern and risk factors for mortality among very low birth weight (VLBW) neonates with NEC in a middle-income setting.

METHODS

A retrospective observational cohort study was conducted on all infants with birth weights less than 1501 g admitted from 2018 to 2020 at Groote Schuur Hospital, Cape Town, South Africa. Data were obtained from the Vermont Oxford Network and hospital folders.

RESULTS

A total of 104/1582 (6.6%) neonates were diagnosed with NEC with a median onset of 8 days of life. The mortality rate was 39.0%, compared to the all-cause mortality rate of 18.7% for VLBW neonates. Thirty-two (32.0%) neonates with NEC were transferred for surgery of whom 10 (31.3%) died. Small for gestational age (p = 0.13), NEC stage 2B or above (p = 0,002), a positive blood culture (p = 0.018), a raised C-reactive protein (p = 0.013), hyponatraemia (p = 0.004), anaemia requiring blood transfusion (p = 0.003) and thrombocytopenia requiring platelet transfusion (p = 0.033) were associated with mortality. A positive blood culture was found in 37.0% with a predominance of Klebsiella pneumoniae isolates.

CONCLUSION

NEC has an early onset and a high mortality rate in our setting.

Analysis of Postoperative Outcomes and Extrauterine Growth Retardation in Preterm Infants with Necrotizing Enterocolitis: A Retrospective Study

OBJECTIVE

High mortality and extrauterine growth retardation (EUGR) remain serious problems in preterm infants after necrotizing enterocolitis (NEC) surgery. This study investigated the risk factors for mortality and EUGR in preterm infants after NEC surgery.

STUDY DESIGN

The risk factors were analyzed retrospectively by univariate analysis and multivariate logistic regression analysis in 52 preterm infants, who underwent NEC surgery and were hospitalized in neonatology department of Shanghai Children's Hospital between May 2014 and December 2021. Patients were divided into survival and death groups. Survivors were divided into two groups according to whether EUGR occurred when they achieved full enteral feeding after surgery.

RESULTS

The mortality of preterm infants after NEC surgery was 26.9% (14/52). About 55.3% (21/38) of survivors developed postoperative EUGR. (1) Age at surgery, proportion of shock, and intestinal perforation differed significantly between the survival and death groups (p = 0.001, 0.005, and 0.02, respectively). Shock (p = 0.02, odds ratio [OR] = 8.86, 95% confidence interval [CI]: 1.43-55.10) and intestinal perforation (p = 0.03, OR = 6.12, 95% CI: 1.16-32.41) were significant risk factors for death. (2) Compared with the non-EUGR group, proportion of preoperative EUGR, postoperative 1-week calories, and parenteral nutrition time differed significantly in EUGR group (p = 0.001, 0.01, and 0.04, respectively). Preoperative EUGR (p = 0.02, OR = 18.63, 95%CI: 1.77-196.42) was a significant risk factor for postoperative EUGR.

CONCLUSION

Shock and intestinal perforation are significant risk factors for death in preterm infants after NEC surgery. Survivors are prone to EUGR, and preoperative EUGR is a significant risk factor. In addition, adequate caloric intake and achievement of full enteral feeding as soon as possible may be beneficial to improve EUGR of preterm infants after NEC surgery.

KEY POINTS

· Shock and intestinal perforation are risk factors for death in preterm infants after NEC surgery.. · Preoperative EUGR is a risk factor for postoperative EUGR in preterm infants after NEC surgery.. · Active correction of shock and avoiding intestinal perforation may help improve the outcomes..

Risk factors of necrotizing enterocolitis in twin preterm infants

PURPOSE

This study was aimed to investigate the risk factors of necrotizing enterocolitis (NEC) in twin preterm infants.

METHODS

The clinical data of 67 pairs of twin preterm infants admitted to the neonatal department of our hospital from January 2010 to December 2021 were retrospectively collected. One of the twins had NEC (Bell II and above) and the other twin without NEC. They were divided into NEC group and control group according to whether NEC occurred or not.

RESULTS

Univariate analysis showed that NEC was associated with congenital heart disease, small for gestational age, mild asphyxia at birth and feeding intolerance (P < 0.05).

CONCLUSION

Occurrence of NEC was associated with congenital heart disease, small for gestational age, and asphyxia at birth. For twin preterm infants with congenital heart disease, small for gestational age, or asphyxia at birth, special attention should be paid to the occurrence of NEC to minimize and avoid the occurrence of NEC.

Necrotizing enterocolitis: current understanding of the prevention and management

Necrotizing enterocolitis (NEC) is one of the diseases in neonates, with a high morbidity and mortality rate, especially in preterm infants. This review aimed to briefly introduce the latest epidemiology, susceptibility factors, and clinical diagnosis and presentation of NEC. We also organized new prevention strategies by risk factors according to different pathogeneses and then discussed new treatment methods based on Bell's staging and complications, and the classification of mild to high severity based on clinical and imaging manifestations. Such a generalization will help clinicians and researchers to gain a deeper understanding of the disease and to conduct more targeted classification, grading prevention, and exploration. We focused on prevention and treatment of the early and suspected stages of NEC, including the discovery of novel biomarkers and drugs to control disease progression. At the same time, we discussed its clinical application, future development, and shortcomings.

Clostridium scindens exacerbates experimental necrotizing enterocolitis via upregulation of the apical sodium-dependent bile acid transporter

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in premature infants. Evidence indicates that bile acid homeostasis is disrupted during NEC: ileal bile acid levels are elevated in animals with experimental NEC, as is expression of the apical sodium-dependent bile acid transporter (Asbt). In addition, bile acids, which are synthesized in the liver, are extensively modified by the gut microbiome, including via the conversion of primary bile acids to more cytotoxic secondary forms. We hypothesized that the addition of bile acid-modifying bacteria would increase susceptibility to NEC in a neonatal rat model of the disease. The secondary bile acid-producing species Clostridium scindens exacerbated both incidence and severity of NEC. C. scindens upregulated the bile acid transporter Asbt and increased levels of intraenterocyte bile acids. Treatment with C. scindens also altered bile acid profiles and increased hydrophobicity of the ileal intracellular bile acid pool. The ability of C. scindens to enhance NEC requires bile acids, as pharmacological sequestration of ileal bile acids protects animals from developing disease. These findings indicate that bile acid-modifying bacteria can contribute to NEC pathology and provide additional evidence for the role of bile acids in the pathophysiology of experimental NEC.NEW & NOTEWORTHY Necrotizing enterocolitis (NEC), a life-threatening gastrointestinal emergency in premature infants, is characterized by dysregulation of bile acid homeostasis. We demonstrate that administering the secondary bile acid-producing bacterium Clostridium scindens enhances NEC in a neonatal rat model of the disease. C. scindens-enhanced NEC is dependent on bile acids and driven by upregulation of the ileal bile acid transporter Asbt. This is the first report of bile acid-modifying bacteria exacerbating experimental NEC pathology.

An Exploratory Analysis of Gastrointestinal Morbidities and Feeding Outcomes Associated with Neonatal Hypoxic-Ischemic Encephalopathy With or Without Hypothermia Therapy

This study investigates the clinical profile and predictors of gastrointestinal/hepatic morbidities and feeding outcomes among neonates with hypoxic-ischemic encephalopathy (HIE). A single-center retrospective chart review of consecutive neonates >35 weeks of gestation admitted with a diagnosis of HIE between January 1, 2015, and December 31, 2020, and treated with therapeutic hypothermia, if met the institutional eligibility criteria. Outcomes assessed included necrotizing enterocolitis (NEC), conjugated hyperbilirubinemia, hepatic dysfunction, assisted feeding at discharge, and time to reach full enteral and oral feeds. Among 240 eligible neonates (gestational age 38.7 [1.7] weeks, birth weight 3279 [551] g), 148 (62%) received hypothermia therapy, and 7 (3%) and 5 (2%) were diagnosed with stage 1 NEC and stage 2-3 NEC, respectively. Twenty-nine (12%) were discharged home with a gastrostomy/gavage tube, conjugated hyperbilirubinemia (first week 22 [9%], at discharge 19 [8%]), and hepatic dysfunction (74 [31%]). Time to reach full oral feeds was significantly longer in hypothermic neonates compared with neonates who did not receive hypothermia (9 [7-12] days vs. 4.5 [3-9] days, p < 0.0001). Factors significantly associated with NEC were renal failure (odds ratio [OR] 9.24, 95% confidence interval [CI] 2.7-33), hepatic dysfunction (OR 5.69, 95% CI 1.6-26), and thrombocytopenia (OR 3.6, 95% CI 1.1-12), but no significant association with hypothermia, severity of brain injury, or stage of encephalopathy. Transient conjugated hyperbilirubinemia, hepatic dysfunction within first week of life, and need for assistive feeding are more common than NEC in HIE. Risk of NEC was associated with the severity of end-organ dysfunction in the first week of life, rather than severity of brain injury and hypothermia therapy per se.

Effective alternatives for dietary interventions for necrotizing enterocolitis: a systematic review of in vivo studies

Necrotizing enterocolitis (NEC) is a significant cause of morbidity and mortality among neonates and low birth weight children in the United States. Current treatment options, such as antibiotics and intestinal resections, often result in complications related to pediatric nutrition and development. This systematic review aimed to identify alternative dietary bioactive compounds that have shown promising outcomes in ameliorating NEC in vivo studies conducted within the past six years. Following PRISMA guidelines and registering in PROSPERO (CRD42023330617), we conducted a comprehensive search of PubMed, Scopus, and Web of Science. Our analysis included 19 studies, predominantly involving in vivo models of rats (Rattus norvegicus) and mice (Mus musculus). The findings revealed that various types of compounds have demonstrated successful amelioration of NEC symptoms. Specifically, six studies employed plant phenolics, seven utilized plant metabolites/cytotoxic chemicals, three explored the efficacy of vitamins, and three investigated the potential of whole food extracts. Importantly, all administered compounds exhibited positive effects in mitigating the disease. These results highlight the potential of natural cytotoxic chemicals derived from medicinal plants in identifying and implementing powerful alternative drugs and therapies for NEC. Such approaches have the capacity to impact multiple pathways involved in the development and progression of NEC symptoms.

A prediction model for neonatal necrotizing enterocolitis in preterm and very low birth weight infants

Objectives

Neonatal necrotizing enterocolitis (NEC) is a severe gastrointestinal disease that primarily affects preterm and very low birth weight infants, with high morbidity and mortality. We aim to build a reliable prediction model to predict the risk of NEC in preterm and very low birth weight infants.

Methods

We conducted a retrospective analysis of medical data from infants (gestational age <32 weeks, birth weight <1,500 g) admitted to Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region. We collected clinical data, randomly dividing it into an 8:2 ratio for training and testing. Multivariate logistic regression was employed to identify significant predictors for NEC. Principal component analysis was used for dimensionality reduction of numerical variables. The prediction model was constructed through logistic regression, incorporating all relevant variables. Subsequently, we calculated performance evaluation metrics, including Receiver Operating Characteristic (ROC) curves and confusion matrices. Additionally, we conducted model performance comparisons with common machine learning models to establish its superiority.

Results

A total of 292 infants were included, with 20% (n = 58) randomly selected for external validation. Multivariate logistic regression revealed the significance of four predictors for NEC in preterm and very low birth weight infants: temperature (P = 0.003), Apgar score at 5 min (P = 0.004), formula feeding (P = 0.007), and gestational diabetes mellitus (GDM, P = 0.033). The model achieved an accuracy of 82.46% in the test set with an F1 score of 0.90, outperforming other machine learning models (support vector machine, random forest).

Conclusions

Our logistic regression model effectively predicts NEC risk in preterm and very low birth weight infants, as confirmed by external validation. Key predictors include temperature, Apgar score at 5 min, formula feeding, and GDM. This study provides a vital tool for NEC risk assessment in this population, potentially improving early interventions and child survival. However, clinical validation and further research are necessary for practical application.

What is Known About Cow's Milk Protein Allergy in Preterm Infants?

Background: Cow's milk protein allergy (CMPA) is well described in term infants, as opposed to preterm infants. In preterm infants, CMPA shares many gastrointestinal symptoms with necrotizing enterocolitis (NEC). Objectives: To evaluate the presentation of CMPA in preterm infants and to investigate the different diagnostic and therapeutic options. Materials and Methods: We searched for the relevant literature using the medical databases PubMed, Web of Science, and the Cochrane Library. We performed a post hoc analysis on the 25 case reports included in this study. Results: Literature was scarce and heterogeneous. The majority of preterm infants with CMPA were exposed to bovine-based milk proteins before the development of symptoms. The most common clinical manifestations were bloody stools, vomiting, and abdominal distension. Of the 25 cases, only 7 (28%) retained human milk in their diet after diagnosis. In the larger studies, no study has human milk as primary feeding choice after diagnosis. Conclusions: Preterm infants exposed to a type of cow's milk-based formula in their first days of life have a higher risk of developing CMPA. Most of the preterm infants are no longer fed with human milk after the diagnosis of CMPA is made, which is in contrast with current nutrition guidelines in preterm infants. We strongly advocate that human milk with mothers on a cow's milk-free diet is the first choice of feed after the diagnosis of CMPA. Prospective studies are necessary to obtain more information regarding clinical presentation, diagnostic tools, and therapeutic approaches.

SIGIRR gene variants in term newborns with congenital heart defects and necrotizing enterocolitis

Background

Necrotizing enterocolitis (NEC) is a common gastrointestinal emergency among neonates which is characterized by acute intestinal inflammation and necrosis. The main risk factors for NEC are prematurity, low birth weight, and some preexisting health conditions such as congenital heart defects (CHDs). Investigation of the potential genetic predisposition to NEC is a promising approach that might provide new insights into its pathogenesis. One of the most important proteins that play a significant role in the pathogenesis of NEC is Toll-like receptor 4 (TLR4) which recognizes lipopolysaccharide found in Gram-negative bacteria. In intestinal epithelial cells, a protein encoded by the SIGIRR gene is a major inhibitor of TLR4 signaling. A few SIGIRR variants, including rare p.Y168X and p.S80Y, have already been identified in preterm infants with NEC, but their pathogenic significance remains unclear. This study aimed to investigate the spectrum of SIGIRR genetic variants in term newborns with CHD and to assess their potential association with NEC.

Methods and Results

A total of 93 term newborns with critical CHD were enrolled in this study, 33 of them developed NEC. SIGIRR genetic variants were determined by Sanger sequencing of all exons. In total, eight SIGIRR genetic variants were identified, two of which were found only in newborns with NEC (P = 0.12). The rare missense p.S80Y (rs117739035) variant in exon 4 was found in two infants with NEC stage IIA. Two infants with NEC stage III and stage IB carried a novel duplication c. 102_121dup (rs552367848) variant in exon 10 that has not been previously associated with any clinical phenotype.

Conclusions

The presence of both variants only in neonates who developed NEC, together with earlier published data, may suggest their potential contribution to the risk of developing NEC in term infants with CHD and allow planning larger cohort studies to clarify their relevance.

Disruption of Enterohepatic Circulation of Bile Acids Ameliorates Small Bowel Resection Associated Hepatic Injury

BACKGROUND

Massive small bowel resection (SBR) is associated with liver injury and fibrosis. Efforts to elucidate the driving force behind hepatic injury have identified multiple factors, including the generation of toxic bile acid metabolites.

METHODS

Sham, 50% proximal, and 50% distal SBR were carried out in C57BL/6 mice to determine the effect of jejunal (proximal SBR) versus ileocecal resection (distal SBR) on bile acid metabolism and liver injury. Tissues were harvested at 2 and 10-week postoperative timepoints.

RESULTS

When compared with 50% proximal SBR, mice that underwent distal SBR exhibited less hepatic oxidative stress as verified by decreased mRNA expression of tumor necrosis factor-α (TNFα, p ≤ 0.0001), nicotinamide adenine dinucleotide phosphate oxidase (NOX, p ≤ 0.0001), and glutathione synthetase (GSS, p ≤ 0.05). Distal SBR mice also exhibited a more hydrophilic bile acid profile with reduced abundance of insoluble bile acids (cholic acid (CA), taurodeoxycholic acid (TCA), and taurolithocholic acid (TLCA)), and increased abundance of soluble bile acids (tauroursodeoxycholic acid (TUDCA)). In contrast with proximal SBR, ileocecal resection alters enterohepatic circulation leading to reduced oxidative stress and promotes physiological bile acid metabolism.

CONCLUSION

These findings challenge the notion that preservation of the ileocecal region is beneficial in patients with short bowel syndrome. Administration of selected bile acids may present potential therapy to mitigate resection-associated liver injury.

LEVEL OF EVIDENCE

III-Case-Control Study.

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.

Necrotizing Enterocolitis: The Role of Hypoxia, Gut Microbiome, and Microbial Metabolites

Necrotizing enterocolitis (NEC) is a life-threatening disease that predominantly affects very low birth weight preterm infants. Development of NEC in preterm infants is accompanied by high mortality. Surgical treatment of NEC can be complicated by short bowel syndrome, intestinal failure, parenteral nutrition-associated liver disease, and neurodevelopmental delay. Issues surrounding pathogenesis, prevention, and treatment of NEC remain unclear. This review summarizes data on prenatal risk factors for NEC, the role of pre-eclampsia, and intrauterine growth retardation in the pathogenesis of NEC. The role of hypoxia in NEC is discussed. Recent data on the role of the intestinal microbiome in the development of NEC, and features of the metabolome that can serve as potential biomarkers, are presented. The Pseudomonadota phylum is known to be associated with NEC in preterm neonates, and the role of other bacteria and their metabolites in NEC pathogenesis is also discussed. The most promising approaches for preventing and treating NEC are summarized.

The role of vitamin D receptor gene polymorphism in the development of necrotizing enterocolitis

BACKGROUND

Vitamin D and its receptor (VDR) effects on the gastrointestinal system are among its most critical multisystemic effects.

METHODS

This study aimed to reveal that VDR gene polymorphisms may constitute a risk factor for necrotizing enterocolitis (NEC). VDR Fok1-Bsm1-Apa single-nucleotide polymorphisms were analyzed in the NEC group (n = 74) and the control group (n = 147). Among 1112 babies at and below 36 weeks of gestational age who were hospitalized between January 2013 and December 2016 with a diagnosis of prematurity, 74 of a total of 148 patients who developed NEC during follow-up (NEC group) were included in the study. When NEC was diagnosed according to clinical and radiological findings and staged using Modified Bell criteria, 9 (12.1%) of 74 babies were stage 1A, 13 (17.5%) stage 1B, and 5 (6.7%) stage 2A, 33 (44.5%) stage 2B, 7 (9.4%) stage 3A, 7 (9.4%) stage 3B. Of 964 babies who did not develop NEC during follow-up, 147 were included as the control group in the study. Genotyping of VDR polymorphisms was assayed by real-time PCR. From 221 premature babies in the NEC and control groups, 2 ml peripheral blood was taken appropriately and meticulously into an EDTA tube. DNA was isolated from these blood samples. DNA amplification was performed using a thermal cycler (Applied Biosystems GeneAmp PCR System 9600).

RESULTS

When the two groups were compared in terms of the prevalence of VDR Fok1 C/T genotype, it was found that TT genotype increased the risk of NEC by 2.697 times, and there was a significant relationship between TT genotype and the risk of NEC (p = 0.041). Multivariable logistic regression analysis was performed in terms of gestational age, birth weight, VDR gene polymorphism data between NEC and the control group. According to the analysis results, TT polymorphism, increased the risk of disease 4.5 times (p = 0.033).

CONCLUSION

Fok 1 C > T polymorphism in the VDR gene plays a role in the development of NEC. Identifying the risk groups by detecting gene polymorphisms that cause increased susceptibility to NEC may assist in the follow-up of these patients and in making early treatment decisions for them.

IMPACT

In this study examining the non-bone effects of the genetic differences in vitamin D metabolism in premature babies, Fok 1 polymorphism has been observed to be an essential risk factor for NEC. This is the first study in our country that has investigated the relationship between VDR gene polymorphism and necrotizing enterocolitis among the Turkish population. Identifying the risk groups by detecting gene polymorphisms that cause increased susceptibility to NEC may assist in the monitoring of these patients and in making early treatment decisions for them.

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.

Compositional Differences of Meconium Microbiomes of Preterm and Term Infants, and Infants That Developed Necrotizing Enterocolitis or Feeding Intolerance

The primary aim of this study was to investigate the compositional differences of the first passed meconium microbiome in preterm and term infants, and the secondary aim was to compare the meconium microbiomes of preterm and term infants that later developed necrotizing enterocolitis (NEC)/Feeding intolerance (FI) compared to those that did not develop NEC/FI. During the study period, a total of 108 preterm and term newborns' first passed meconium occurring within 72 hours of birth were collected and microbiome analyzed. Meconium microbiomes showed a disruption in the percentages of the core microbiome constituents in both the phylum and genus levels in infants born < 30 weeks of gestational age (GA) compared to those born ≥ 30 weeks of GA. In the phylum level, Bacteroidetes and Firmicutes, and in the genus level, Prevotella and Bacteroides, were predominant, with Prevotella accounting for 20−30% of the relative abundance. As GA increased, a significant increase in the relative abundance of Bacteroidetes (P for trend < 0.001) and decrease in Proteobacteria (P for trend = 0.049) was observed in the phylum level. In the genus level, as GA increased, Prevotella (P for trend < 0.001) and Bacteroides (P for trend = 0.002) increased significantly, whereas Enterococcus (P for trend = 0.020) decreased. Compared to the control group, the meconium of infants that later developed NEC/FI had significantly lower alpha diversities but similar beta-diversities. Furthermore, the NEC/FI group showed a significantly lower abundance of Bacteroidetes (P < 0.001), and higher abundance of Firmicutes (P = 0.034). To conclude, differences were observed in the composition of the first passed meconium in preterm and term infants that later develop NEC/FI compared to those that did not.

Intra-Amniotic Administration-An Emerging Method to Investigate Necrotizing Enterocolitis, In Vivo (Gallus gallus)

Necrotizing enterocolitis (NEC) is a severe gastrointestinal disease in premature infants and a leading cause of death in neonates (1-7% in the US). NEC is caused by opportunistic bacteria, which cause gut dysbiosis and inflammation and ultimately result in intestinal necrosis. Previous studies have utilized the rodent and pig models to mimic NEC, whereas the current study uses the in vivo (Gallus gallus) intra-amniotic administration approach to investigate NEC. On incubation day 17, broiler chicken (Gallus gallus) viable embryos were injected intra-amniotically with 1 mL dextran sodium sulfate (DSS) in H₂O. Four treatment groups (0.1%, 0.25%, 0.5%, and 0.75% DSS) and two controls (H₂O/non-injected controls) were administered. We observed a significant increase in intestinal permeability and negative intestinal morphological changes, specifically, decreased villus surface area and goblet cell diameter in the 0.50% and 0.75% DSS groups. Furthermore, there was a significant increase in pathogenic bacterial (E. coli spp. and Klebsiella spp.) abundances in the 0.75% DSS group compared to the control groups, demonstrating cecal microbiota dysbiosis. These results demonstrate significant physiopathology of NEC and negative bacterial-host interactions within a premature gastrointestinal system. Our present study demonstrates a novel model of NEC through intra-amniotic administration to study the effects of NEC on intestinal functionality, morphology, and gut microbiota in vivo.

Neonatal multiple organ failure after perinatal asphyxia

Perinatal asphyxia is an event with far-reaching consequences that can lead not only to the development of neonatal encephalopathy, but also to multiple organ failure (MOF). This ailment may result from the redistribution of blood flow, which would preserve the perfusion of vital organs such as the heart, brain and adrenal glands at the expense of other organs. The objective of the study was to determine the incidence and aetiopathogenesis of failure in the organs most frequently involved in neonatal MOF following perinatal asphyxia. We conducted a systematic literature search in the PubMed, Scopus and Cochrane Library databases using the MeSH terms (ischemia AND hypoxia AND multiorgan dysfunction AND neonat*), (asphyxia AND multiorgan dysfunction AND neonat*) and (liver/kidney/digestive OR gastrointestinal/heart injury AND ischemia AND hypoxia AND neonat*). We selected clinical and preclinical studies published after 2000 and excluded case series, letters to the editor, cohort studies without comparison groups and abstracts. In this study, we found that MOF associated with perinatal asphyxia is a frequent phenomenon with a relevant impact on neonatal morbidity and mortality, as it can cause changes not only in the kidney, liver and gastrointestinal tract, but also cardiomyopathy if the ailment is protracted or severe.

Gut microbiota and short-chain fatty acids may be new biomarkers for predicting neonatal necrotizing enterocolitis: A pilot study

Background

Dysbacteriosis is thought to play an important role in the pathogenesis of necrotizing enterocolitis (NEC). We aimed to identify new biomarkers among gut microbiota and short-chain fatty acids (SCFAs) for the early prediction of NEC.

Materials and methods

Thirty-four preterm infants with gestational ages of ≤ 34 weeks who developed gastrointestinal symptoms were divided into the NEC group (n = 17) and non-NEC group (n = 17). In the NEC group, the gut microbiota and SCFAs in feces were assessed when the infants were enrolled (Group P) and when they were diagnosed with NEC (Group N). In the non-NEC group, samples were assessed when the infants were enrolled (Group C).

Results

The Ace and Chao1 indices were higher in Group P than in Group C (P &lt; 0.05), and there was no difference between Groups C and N or between Groups P and N (P &gt; 0.05). There was no significant difference in the Simpson and Shannon indices among Groups C, P and N (P &gt; 0.05). The four main phyla showed no differences (P &gt; 0.05) in composition, while at the genus level, compared with Group C, in Group P, Clostridioides, Blautia and Clostridium_sensu_stricto_1 were increased, while Lactobacillus and Bifidobacterium were decreased (P &lt; 0.05). At the species level, Streptococcus salivarius and Rothia mucilaginosa increased, while Bifidobacterium animals subsp. lactis decreased (P &lt; 0.05). In Group N, at the genus level, Stenotrophomonas, Streptococcus and Prevotella increased (P &lt; 0.05). Compared with those in Group C, the levels of acetic acid, propanoic acid and butyric acid decreased significantly in Groups P and N (P &lt; 0.05), and the areas under the curves (AUCs) of these three SCFAs between groups C and P were 0.73, 0.70, and 0.68, respectively.

Conclusion

The increase in Streptococcus salivarius and Rothia mucilaginosa and decrease in Bifidobacterium_animals_subsp._lactis, as well as the decrease in acetic, propionic and butyric acids, may help in the early prediction of NEC.

Fast Feed Advancement for Preterm and Low Birth Weight Infants: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

Fast feed advancement may reduce hospital stay and infection but may increase adverse outcomes in preterm and low birth weight infants. The objective of this study was to assess effects of fast feed advancement (≥30 ml/kg per day) compared with slow feed advancement (<30 ml/kg per day) in preterm and low birth weight infants.

METHODS

Data sources include Medline, Scopus, Web of Science, CINAHL, and Index Medicus through June 30, 2021. Randomized trials were selected. Primary outcomes were mortality, morbidity, growth, and neurodevelopment. Data were extracted and pooled using random-effects models. The Cochrane Risk of Bias 2 tool was used.

RESULTS

A total of 12 RCTs with 4291 participants were included. At discharge, there was moderate certainty evidence that fast advancement likely slightly reduces the risk of: mortality (relative risk [RR] 0.93, 95% confidence interval [95% CI] 0.73 to 1.18, I2 = 18%, 11 trials, 4132 participants); necrotizing enterocolitis (RR 0.89, 95% CI 0.68 to 1.15, I2 = 0%, 12 trials, 4291 participants); sepsis (RR 0.92, 95% CI 0.83 to 1.03, I2 = 0%, 9 trials, 3648 participants); and feed intolerance (RR 0.92, 95% CI 0.77 to 1.10, I2 = 0%, 8 trials, 1114 participants). Fast feed advancement may also reduce the risk of apnea (RR 0.72, 95% CI 0.47 to 1.12, I2 = 0%, low certainty, 2 trials, 153 participants). Fast feed advancement decreases time to regain birth weight (mean difference [MD] -3.69 days, 95% CI -4.44 to -2.95, I2 = 70%, high certainty, 6 trials, 993 participants,) and likely reduces the duration of hospitalization (MD -3.08 days, 95% CI -4.34 to -1.81, I2 = 77%, moderate certainty, 7 trials, 3864 participants). Limitations include heterogeneity between studies and small sample sizes.

CONCLUSIONS

Fast feed advancement reduces time to regain birth weight and likely reduces the length of hospital stay; it also likely reduces the risk of neonatal morbidity and mortality slightly. However, it may increase the risk of neurodevelopmental disability slightly. More studies are needed to understand the long-term effects of fast feed advancement.

[Establishment of a nomogram model for predicting necrotizing enterocolitis in very preterm infants]

OBJECTIVES

To investigate the risk factors for necrotizing enterocolitis (NEC) in very preterm infants and establish a nomogram model for predicting the risk of NEC.

METHODS

A total of 752 very preterm infants who were hospitalized from January 2015 to December 2021 were enrolled as subjects, among whom 654 were born in 2015-2020 (development set) and 98 were born in 2021 (validation set). According to the presence or absence of NEC, the development set was divided into two groups: NEC (n=77) and non-NEC (n=577). A multivariate logistic regression analysis was used to investigate the independent risk factors for NEC in very preterm infants. R software was used to plot the nomogram model. The nomogram model was then validated by the data of the validation set. The receiver operating characteristic (ROC) curve, the Hosmer-Lemeshow goodness-of-fit test, and the calibration curve were used to evaluate the performance of the nomogram model, and the clinical decision curve was used to assess the clinical practicability of the model.

RESULTS

The multivariate logistic regression analysis showed that neonatal asphyxia, sepsis, shock, hypoalbuminemia, severe anemia, and formula feeding were independent risk factors for NEC in very preterm infants (P<0.05). The ROC curve of the development set had an area under the curve (AUC) of 0.833 (95%CI: 0.715-0.952), and the ROC curve of the validation set had an AUC of 0.826 (95%CI: 0.797-0.862), suggesting that the nomogram model had a good discriminatory ability. The calibration curve analysis and the Hosmer-Lemeshow goodness-of-fit test showed good accuracy and consistency between the predicted value of the model and the actual value.

CONCLUSIONS

Neonatal asphyxia, sepsis, shock, hypoalbuminemia, severe anemia, and formula feeding are independent risk factors for NEC in very preterm infant. The nomogram model based on the multivariate logistic regression analysis provides a quantitative, simple, and intuitive tool for early assessment of the development of NEC in very preterm infants in clinical practice.

Donor-dependent fecal microbiota transplantation efficacy against necrotizing enterocolitis in preterm pigs

The development of necrotizing enterocolitis (NEC), a life-threatening inflammatory bowel disease affecting preterm infants, is connected with gut microbiota dysbiosis. Using preterm piglets as a model for preterm infants we recently showed that fecal microbiota transplantation (FMT) from healthy suckling piglet donors to newborn preterm piglets decreased the NEC risk. However, in a follow-up study using donor stool from piglets recruited from another farm, this finding could not be replicated. This allowed us to study donor-recipient microbiota dynamics in a controlled model system with a clear difference in NEC phenotype. Preterm piglets (n = 38) were randomly allocated to receive control saline (CON), or rectal FMT using either the ineffective (FMT1) or the effective donor stool (FMT2). All animals were followed for four days before necropsy and gut pathological evaluation. Donor and recipient colonic gut microbiota (GM) were analyzed by 16 S rRNA gene amplicon sequencing and shotgun metagenomics. As expected, only FMT2 recipients were protected against NEC. Both FMT groups had shifted GM composition relative to CON, but FMT2 recipients had a higher lactobacilli relative abundance compared to FMT1. Limosilactobacillus reuteri and Lactobacillus crispatus strains of FMT recipients showed high phylogenetic similarity with their respective donors, indicating engraftment. Moreover, the FMT2 group had a higher lactobacilli replication rate and harbored specific glycosaminoglycan-degrading Bacteroides. In conclusion, subtle species-level donor differences translate to major changes in engraftment dynamics and the ability to prevent NEC. This could have implications for proper donor selection in future FMT trials for NEC prevention.

Enteric Nervous System in Neonatal Necrotizing Enterocolitis

BACKGROUND

The pathophysiology of necrotizing enterocolitis (NEC) is not clear, but increasing information suggests that the risk and severity of NEC may be influenced by abnormalities in the enteric nervous system (ENS).

OBJECTIVE

The purpose of this review was to scope and examine the research related to ENS-associated abnormalities that have either been identified in NEC or have been noted in other inflammatory bowel disorders (IBDs) with histopathological abnormalities similar to NEC. The aim was to summarize the research findings, identify research gaps in existing literature, and disseminate them to key knowledge end-users to collaborate and address the same in future studies.

METHODS

Articles that met the objectives of the study were identified through an extensive literature search in the databases PubMed, EMBASE, and Scopus.

RESULTS

The sources identified through the literature search revealed that: (1) ENS may be involved in NEC development and post-NEC complications, (2) NEC development is associated with changes in the ENS, and (3) NEC-associated changes could be modulated by the ENS.

CONCLUSION

The findings from this review identify the enteric nervous as a target in the development and progression of NEC. Thus, factors that can protect the ENS can potentially prevent and treat NEC and post-NEC complications. This review serves to summarize the existing literature and highlights a need for further research on the involvement of ENS in NEC.

Necrotizing enterocolitis in the preterm: newborns medical and nutritional Management in a Single-Center Study

Necrotizing enterocolitis (NEC) is a typical disorder of preterm newborns, with a high mortality and morbidity rate. The therapeutic and nutritional management of disease depends on several factors. Its prognosis is linked, in addition to the severity of the disease and the need for surgery, to a correct enteral feeding in these patients. This study aims to identify the clinical characteristics of 18 patients with NEC, evaluating the different therapeutic paths undertaken, the type of formula used and the survival rate of this population. Average time of enteral nutrition before the NEC onset was 11,3 ± 11,6 days, with an average fasting period since the onset of 24 ± 18.9 days. 77.8% of patients received surgery and resumed enteral nutrition 17.7 ± 17.9 days after the intervention. The overall survival rate of our cohort was 55.5%. More prospective studies are needed to evaluate the long-term outcomes of survived children with NEC.

Necrotizing Enterocolitis: Overview on In Vitro Models

Necrotizing enterocolitis (NEC) is a gut inflammatory disorder which constitutes one of the leading causes of morbidity and mortality for preterm infants. The pathophysiology of NEC is yet to be fully understood; several observational studies have led to the identification of multiple factors involved in the pathophysiology of the disease, including gut immaturity and dysbiosis of the intestinal microbiome. Given the complex interactions between microbiota, enterocytes, and immune cells, and the limited access to fetal human tissues for experimental studies, animal models have long been essential to describe NEC mechanisms. However, at present there is no animal model perfectly mimicking human NEC; furthermore, the disease mechanisms appear too complex to be studied in single-cell cultures. Thus, researchers have developed new approaches in which intestinal epithelial cells are exposed to a combination of environmental and microbial factors which can potentially trigger NEC. In addition, organoids have gained increasing attention as promising models for studying NEC development. Currently, several in vitro models have been proposed and have contributed to describe the disease in deeper detail. In this paper, we will provide an updated review of available in vitro models of NEC and an overview of current knowledge regarding its molecular underpinnings.

Surgical Versus Medical Management of Necrotizing Enterocolitis With and Without Intestinal Perforation: A Retrospective Chart Review

Background

Necrotizing enterocolitis (NEC) is a debilitating disease that predominantly afflicts premature neonates, although it can also affect term neonates. The clinical features of the ailment vary widely and range from transient feed intolerance to life-threatening complications such as septicemia and disseminated intravascular coagulation. While surgery is usually only reserved for severe cases, such as those presenting with intestinal perforation, the role of surgical management in cases of NEC without perforation remains elusive.

Methods

A retrospective chart review of patients, three years in duration, was conducted and studied confirmed cases of NEC. The clinical presentations studied included cases of NEC with pneumatosis intestinalis, fixed bowel loop, pneumoperitoneum, and abdominal wall erythema. The patients were divided with regards to their intestinal perforation status and with pertinence to the treatment modality employed (medical or surgical). The results in either group were eventually analyzed in terms of the overall survival rate.

Results

A total of 48 patients were included in the study, of which 79.16% presented without perforation and 20.83% with perforation. Of the study participants included, 26 were females and 22 were males. Pertinently, no gender predominance was appreciated. In patients without perforation, medical management was noted to boast a lower mortality rate when compared with surgical intervention (15.6% vs 50.0%, respectively). In patients with perforation, the overall mortality was noted to hover at 50.0%, which was higher than that encountered in the non-perforation group.

Conclusion

In patients with NEC without perforation, surgical treatment confers no comparative therapeutic advantage when compared with medical management alone. Conservative management with broad-spectrum antibiotics including metronidazole yields equally favorable outcomes in such cases.

Sialylated human milk oligosaccharides prevent intestinal inflammation by inhibiting toll like receptor 4/NLRP3 inflammasome pathway in necrotizing enterocolitis rats

Background

Necrotizing enterocolitis (NEC) remains a fatal gastrointestinal disorder in neonates and has very limited therapeutic options. Sialylated human milk oligosaccharides (SHMOs) improve pathological changes in experimental NEC models. The objectives of this study were to investigate the involvement of NLRP3 inflammasome in NEC pathology and to explore the effects of SHMOs on toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB)/NLRP3 inflammatory pathway in experimental NEC.

Methods

The intestinal-tissue segments were collected from NEC infants, NLRP3 and caspase-1 positive cell were examined by immunohistochemistry. Newborn rats were hand-fed with formula containing or non-containing SHMOs (1500 mg/L) and exposed to hypoxia/cold stress to induce experimental NEC. The NEC pathological scores were evaluated; ileum protein expression of membrane TLR4 (mTLR4), inhibitor κB-α (IκB-α), NF-κB p65 subunit and phospho-NF-κB p65, as well as NLRP3 and caspase-1 were analyzed; ileum concentrations of interleukin-1β, interleukin-6, tumor necrosis factor-α (TNF-α) were also measured. Human colon epithelial Caco-2 cells were pre-treated with or without SHMOs and stimulated with TLR4 activator, lipopolysaccharide. Cell viabilities, mitochondrial membrane potential and supernatant matrix metalloprotease 2 (MMP-2) activities were analyzed.

Results

Increased frequencies of NLRP3 and caspase-1 positive cells were found in the lamina propria of damaged intestinal area of NEC neonates. SHMOs supplementation reduced NEC incidence and pathological damage scores of rats challenged with hypoxia/cold stress. Accumulation of interleukin-1β, interleukin-6 and TNF-α in NEC group were attenuated in SHMOs + NEC group. Protein expression of mTLR4, NLRP3 and caspase-1 were elevated, cytoplasmic IκB-α were reduced, nuclear phospho-NF-κB p65 were increased in the ileum of NEC rats. SHMOs supplementation ameliorated the elevation of mTLR4, NLRP3 and caspase-1, restored IκB-α in the cytoplasmic fraction and reduced phospho-NF-κB p65 in the nuclear fraction in the ileum of NEC rats. SHMOs pre-treatment improved Caco-2 cell viability, mitigated loss of mitochondrial membrane potential and modulated MMP-2 activities in the presence of lipopolysaccharide in-vitro.

Conclusions

This study provided clinical evidence of involvement of NLRP3 inflammasome in NEC pathology, and demonstrated the protective actions of SHMOs might be owing to the suppression of TLR4/NF-κB/NLRP3-mediated inflammation in NEC.

Interleukin 8 may predict surgical necrotizing enterocolitis in infants born less than 1500 g

Necrotizing enterocolitis (NEC) often leads to gastrointestinal emergency resulting high mortality in very low birth weight infants (VLBWIs) requiring surgery. To date, few studies have explored the role of serum cytokines in the development of feeding intolerance (FI) or NEC outcomes in VLBWIs. Infants born weighing <1500 g or of 32 weeks of gestational age were prospectively enrolled from May 2018 to Dec 2019. We measured several cytokines routinely within 72 h of life, even before NEC-like symptoms developed. NEC or FI group comprised 17 (27.4%) infants, and 6 (9.7%) infants had surgical NEC. The gestational age and birth weight were significantly lower in the NEC or FI group with more prematurity-related complications. The surgical NEC group also demonstrated significantly lower gestational age and birth weight along with more infants experiencing refractory hypotension within a 1 week of life, pulmonary hypertension, and patent ductus arteriosus. IL-10 levels were significantly higher in the NEC or FI group, whereas IL-8 levels were significantly higher in the infants with surgical NEC. Our findings indicated to IL-8 can predict surgical NEC while increased IL-10 can predict NEC development in VLBWIs.

Maternal administration of probiotics promotes gut development in mouse offsprings

Necrotizing enterocolitis is the most common gastrointestinal disorder in premature neonates. This disease is characterized by massive epithelial necrosis, gut barrier dysfunction and improper mucosal defense development. Studies have shown that probiotic administration can decrease NEC incidence and mortality. The proposed mechanisms of probiotics for the prevention of NEC are: promotion of intestinal development; improved barrier function through decreased apoptosis and improved mucin production; decreased expression of proinflammatory cytokines IL6, IL8, and TNFα, and modulation of microbiota dysbiosis in preterm infants. However, reported sepsis in the immunocompromised preterm host has deterred routine prophylactic administration of probiotics in the neonatal intensive care unit. We hypothesize that maternal administration of probiotics to pregnant mouse dams can recapitulate the beneficial effects observed in neonates fed with probiotics directly. We exposed pregnant mice to the probiotics and monitored the changes in the developing intestines of the offspring. Pregnant mice were fed daily with the probiotics Lactobacillus acidophilus and Bifidobacterium infantis (LB) from embryonic day15 to 2-week-old postnatally. Intraperitoneal administration of IL-1β in the pups was used to model proinflammatory insults. Sera were collected at 2 weeks of age and evaluated for inflammatory cytokines by enzyme-linked-immunosorbent-assay and gut permeability by Fluorescein isothiocyanate-dextran tracer assay. Ileal tissues were collected for the evaluation of apoptosis and proliferation of the intestinal epithelium; as well as mucin and tight junction integrity at mucosal surface by immunofluorescent staining. We find that maternal LB exposure facilitated intestinal epithelial cell differentiation, prevented loss of mucin and preserved the intestinal integrity and barrier function and decreased serum levels of IL-1β, TNF-α and IL-6 in the preweaned offsprings. in LB exposed pups. We demonstrate that maternal probiotic supplementation promotes gut maturation in developing offspring. This is potentially a safe alternative therapy to induce intestinal maturation and prevent prematurity-associated neonatal disorders.

Extrapulmonary Surfactant Therapy: Review of Available Data and Research/Development Issues

Since the discovery of surfactant, a large amount of knowledge has been accumulated about its biology and pharmacology. Surfactant is the cornerstone of neonatal respiratory critical care, but its proteins and phospholipids are produced in various tissues and organs, with possible roles only partially similar to that played in the alveoli. As surfactant research is focused mainly on its respiratory applications, knowledge about the possible role of surfactant in extrapulmonary disorders has never been summarized. Here we aim to comprehensively review the data about surfactant biology and pharmacology in organs other than the lung, especially focusing in the more promising surfactant extrapulmonary roles. We also review any preclinical or clinical data available about the therapeutic use of surfactant in these contexts. We offer a summary of knowledge and research/development milestones, as possible useful guidance for researchers of multidisciplinary background.

The Immature Gut Barrier and Its Importance in Establishing Immunity in Newborn Mammals

The gut is an efficient barrier which protects against the passage of pathogenic microorganisms and potential harmful macromolecules into the body, in addition to its primary function of nutrient digestion and absorption. Contrary to the restricted macromolecular passage in adulthood, enhanced transfer takes place across the intestines during early life, due to the high endocytic capacity of the immature intestinal epithelial cells during the fetal and/or neonatal periods. The timing and extent of this enhanced endocytic capacity is dependent on animal species, with a prominent non-selective intestinal macromolecular transfer in newborn ungulates, e.g., pigs, during the first few days of life, and a selective transfer of mainly immunoglobulin G (IgG), mediated by the FcRn receptor, in suckling rodents, e.g., rats and mice. In primates, maternal IgG is transferred during fetal life via the placenta, and intestinal macromolecular transfer is largely restricted in human neonates. The period of intestinal macromolecular transmission provides passive immune protection through the transfer of IgG antibodies from an immune competent mother; and may even have extra-immune beneficial effects on organ maturation in the offspring. Moreover, intestinal transfer during the fetal/neonatal periods results in increased exposure to microbial and food antigens which are then presented to the underlying immune system, which is both naïve and immature. This likely stimulates the maturation of the immune system and shifts the response toward tolerance induction instead of activation or inflammation, as usually seen in adulthood. Ingestion of mother's milk and the dietary transition to complex food at weaning, as well as the transient changes in the gut microbiota during the neonatal period, are also involved in the resulting immune response. Any disturbances in timing and/or balance of these parallel processes, i.e., intestinal epithelial maturation, luminal microbial colonization and mucosal immune maturation due to, e.g., preterm birth, infection, antibiotic use or nutrient changes during the neonatal period, might affect the establishment of the immune system in the infant. This review will focus on how differing developmental processes in the intestinal epithelium affect the macromolecular passage in different species and the possible impact of such passage on the establishment of immunity during the critical perinatal period in young mammals.

Histological analysis of the intestinal wall of newborn rats submitted to hypoxia and reoxygenation to evaluate the protective effect of N-Acetylcysteine

Purpose

To evaluate the effect of N-Acetylcysteine (NAC) in newborn rats submitted to hypoxia and reoxygenation (H/R) conditions in an experimental model of necrotizing enterocolitis.

Methods

Eight pregnant rats and their 70 cubs were used (5 groups) and exposed to H/R conditions and received NAC at different times. The animals in the H/R groups were placed in a gas chamber (100% CO²) for 10 minutes and then reoxygenated for 10 minutes (100% O²), twice a day for the first three days of life, with a six-hour span between events. On the third day of life, the animals were anesthetized, laparotomized and the intestines were resected.

Results

The H/R and NAC groups showed changes in the intestinal wall in relation to the number, height and width of the villi when compared to the control group (p<0.0001), but with better preservation of structures in the NAC group. There were no differences between groups regarding the number (%) of mitoses.

Conclusion

The administration of NAC decreased the lesions in the intestinal wall of rats submitted to H/R, therefore suggesting that this drug can be used to prevent the development of necrotizing enterocolitis in newborns.

Nutrition in Necrotizing Enterocolitis and Following Intestinal Resection

This review aims to discuss the role of nutrition and feeding practices in necrotizing enterocolitis (NEC), NEC prevention, and its complications, including surgical treatment. A thorough PubMed search was performed with a focus on meta-analyses and randomized controlled trials when available. There are several variables in nutrition and the feeding of preterm infants with the intention of preventing necrotizing enterocolitis (NEC). Starting feeds later rather than earlier, advancing feeds slowly and continuous feeds have not been shown to prevent NEC and breast milk remains the only effective prevention strategy. The lack of medical treatment options for NEC often leads to disease progression requiring surgical resection. Following resection, intestinal adaptation occurs, during which villi lengthen and crypts deepen to increase the functional capacity of remaining bowel. The effect of macronutrients on intestinal adaptation has been extensively studied in animal models. Clinically, the length and portion of intestine that is resected may lead to patients requiring parenteral nutrition, which is also reviewed here. There remain significant gaps in knowledge surrounding many of the nutritional aspects of NEC and more research is needed to determine optimal feeding approaches to prevent NEC, particularly in infants younger than 28 weeks and <1000 grams. Additional research is also needed to identify biomarkers reflecting intestinal recovery following NEC diagnosis individualize when feedings should be safely resumed for each patient.

Elevated Coefficient of Variation in Total Fecal Bile Acids Precedes Diagnosis of Necrotizing Enterocolitis

Accumulation of bile acids (BAs) may mediate development of necrotizing enterocolitis (NEC). Serial fecal samples were collected from premature infants with birth weight (BW) ≤ 1800 g, estimated gestational age (EGA) ≤ 32 weeks, and <30 days old prior to initiation of enteral feeding. Nine infants that developed Bell’s Stage ≥ II NEC were matched with control infants based on BW, EGA, day of life (DOL) enteral feeding was initiated and DOL of the first sample. From each subject, five samples matched by DOL collected were analyzed for BA levels and composition. Fifteen individual BA species were measured via LC-MS/MS and total BA levels were measured using the Diazyme Total Bile Acid Assay kit. No statistically significant differences in composition were observed between control and NEC at the level of individual species (p = 0.1133) or grouped BAs (p = 0.0742). However, there was a statistically significant difference (p = 0.000012) in the mean coefficient of variation (CV) between the two groups with infants developing NEC having more than four-fold higher mean CV than controls. Importantly, these variations occurred prior to NEC diagnosis. These data suggest fluctuations in total fecal BA levels could provide the basis for the first predictive clinical test for NEC.

Inconsistent outcome reporting in large neonatal trials: a systematic review

OBJECTIVE

Inconsistent outcome selection and reporting in clinical trials are important sources of research waste; it is not known how common this problem is in neonatal trials. Our objective was to determine whether large clinical trials involving infants receiving neonatal care report a consistent set of outcomes, how composite outcomes are used and whether parents or former patients were involved in outcome selection.

DESIGN

A literature search of CENTRAL, CINAHL, EMBASE and MEDLINE was conducted; randomised trials published between 1 July 2012 and 1 July 2017 and involving at least 100 infants in each arm were included. Outcomes and outcome measures were extracted and categorised by physiological system; reported former patient and parent involvement in outcome selection was extracted.

RESULTS

Seventy-six trials involving 43 126 infants were identified; 216 different outcomes with 889 different outcome measures were reported. Outcome reporting covered all physiological systems but was variable between individual trials: only 67/76 (88%) of trials reported survival and 639 outcome measures were only reported in a single trial. Thirty-three composite outcomes were used in 41 trials. No trials reported former patient or parent involvement in outcome selection.

CONCLUSIONS

Inconsistent outcome reporting and a lack of parent and former patient involvement in outcome selection in neonatal clinical trials limits the ability of such trials to answer clinically meaningful questions. Developing and implementing a core outcome set for future neonatal trials, with input from all stakeholders, should address these issues.

The World Health Organization ACTION-I (Antenatal CorTicosteroids for Improving Outcomes in preterm Newborns) Trial: a multi-country, multi-centre, two-arm, parallel, double-blind, placebo-controlled, individually randomized trial of antenatal corticosteroids for women at risk of imminent birth in the early preterm period in hospitals in low-resource countries

Background

Antenatal corticosteroids (ACS) have long been regarded as a cornerstone intervention in mitigating the adverse effects of a preterm birth. However, the safety and efficacy of ACS in hospitals in low-resource countries has not been established in an efficacy trial despite their widespread use. Findings of a large cluster-randomized trial in six low- and middle-income countries showed that efforts to scale up ACS use in low-resource settings can lead to harm. There is equipoise regarding the benefits and harms of ACS use in hospitals in low-resource countries. This randomized controlled trial aims to determine whether ACS are safe and efficacious when given to women at risk of imminent birth in the early preterm period, in hospitals in low-resource countries.

Methods/design

The trial design is a parallel, two-arm, double-blind, individually randomized, placebo-controlled trial of ACS (dexamethasone) for women at risk of imminent preterm birth. The trial will recruit 6018 women in participating hospitals across five low-resource countries (Bangladesh, India, Kenya, Nigeria and Pakistan). The primary objectives are to compare the efficacy of dexamethasone with placebo on survival of the baby and maternal infectious morbidity. The primary outcomes are: 1) neonatal death (to 28 completed days of life); 2) any baby death (any stillbirth postrandomization or neonatal death); and 3) a composite outcome to assess possible maternal bacterial infections. The trial will recruit eligible, consenting pregnant women from 26 weeks 0 days to 33 weeks 6 days gestation with confirmed live fetuses, in whom birth is planned or expected within 48 h. The intervention comprises a regimen of intramuscular dexamethasone sodium phosphate. The comparison is an identical placebo regimen (normal saline). A total of 6018 women will be recruited to detect a reduction of 15% or more in neonatal deaths in a two-sided 5% significance test with 90% power (including 10% loss to follow-up).

Discussion

Findings of this trial will guide clinicians, programme managers and policymakers on the safety and efficacy of ACS in hospitals in low-resource countries. The trial findings will inform updating of the World Health Organization’s global recommendations on ACS use.

Trial registration

ACTRN12617000476336. Registered on 31 March 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3488-z) contains supplementary material, which is available to authorized users.

Frequencies of Immune Cells in the Human Small Bowel During Normal Gestation and in Necrotizing Enterocolitis

BACKGROUND

Only few studies have quantitated the frequencies of immune cells in the small bowel mucosa and submucosa during gestation. The aims of this study were to describe the frequencies of T and B cells, eosinophils and mast cells in the normal small bowel mucosa and submucosa (NSB) in relation to gestational age (GA) and in the uninvolved small bowel (USB) of premature newborns with necrotizing enterocolitis (NEC).

METHODS

We obtained 36 NSB specimens (GA 12-41 weeks) and 8 NEC-USB specimens (GA 24-32 weeks) from autopsies and surgeries and performed immunostaining for CD3, CD79a, BMK-13 and tryptase as well as the histochemical stains giemsa and toluidine blue. Qualitative histological evaluation and two different quantitative cell-samplings were performed using digital imaging analysis with both TissuemorphDP^® and newCAST® software. Linear regression analysis was performed with cell frequency as the dependent variable and GA and USB as the independent variables.

RESULTS

In the NSB specimens, we found significant linear correlations between cell frequencies and GA for all examined cell types, though B cell frequencies reached a plateau midway through gestation. In the USB cases, submucosal mast cell frequencies were higher than in the NSB specimens, while T cell frequencies were lower. In USB of NEC patients, we found a significant increase of mast cells and a significant decrease of T cells compared to NSB.

CONCLUSION

Throughout gestation, we found an increase of all examined immune cell types in the normal small bowel, while the number of B cells came to a standstill at midway. Future studies should examine subtypes of T cells and also include histiocytes. A larger amount of small bowel specimens, covering the full gestational age, would be of great value.

Necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is an acute inflammatory disease of the intestine which primarily affects preterm infants and is a leading cause of morbidity and mortality in the neonatal intensive care unit. From a clinical standpoint, and during the early course of the disease, NEC can be difficult to distinguish from other diseases and conditions common to the preterm infant, and this warrants the need for specific disease biomarkers. The pathogenesis of NEC is only partly understood but likely involves an altered intestinal barrier immune response to feeding and the developing microbiome. Recent evidence points toward a role of the enteric nervous system in NEC pathogenesis. In this issue, Meister and colleagues use a rodent model of NEC to demonstrate that NEC is associated with diminished vagal tone, as determined by decreased high-frequency heart rate variability (HF-HRV), and altered myenteric nitrergic inhibitory neurotransmission. These results augment their previous findings that describe decreased HF-HRV in human preterm infants with NEC. This mini-review provides a brief summary of clinical and pathophysiologic aspects of NEC with focus on certain aspects of neurogastroenterology.

Epidemiology of Necrotizing Enterocolitis: New Considerations Regarding the Influence of Red Blood Cell Transfusions and Anemia

This article summarizes available evidence on the relationship between red blood cell transfusion and anemia, and necrotizing enterocolitis (NEC). We review recent studies that highlight the uncertainty of the effect of red blood cell transfusion on NEC and the potential role of anemia. We also discuss potential pathophysiologic effects of both red blood cell transfusion and anemia and highlight strategies to prevent anemia and red blood cell transfusion. We also discuss ongoing randomized trials that are likely to provide important new evidence to guide red blood cell transfusion practices.

Recent advances in understanding necrotizing enterocolitis

Necrotizing enterocolitis is a devastating intestinal disease affecting preterm infants. In spite of ongoing research and advancement in neonatal care, mortality remains high, especially in infants with advanced disease. The mechanism of disease development, the progression of intestinal injury, and management remain areas of ongoing research and controversy. In this review, we examine our current understanding of the disease, its epidemiology, the risk factors associated with the development of the disease, and its pathophysiology. We also describe current management and new emerging research highlighting potential future directions.

Degradation of Extracellular DNA Significantly Ameliorates Necrotizing Enterocolitis Severity in Mice

BACKGROUND

Necrotizing enterocolitis (NEC) is one of the most devastating diseases in neonates and is characterized by high morbidity and mortality. It has been suggested that neutrophils play a crucial role in NEC pathogenesis and contribute to the hyperinflammatory reaction after bacterial colonization, which ultimately induces NEC. The aim of this study was to investigate whether dissolution of neutrophil extracellular traps (NETs) by systemic DNase1 therapy reduces NEC manifestation and morbidity.

METHODS

NEC was induced in neonatal mice by gavage feeding of lipopolysaccharide mixed in Neocate, followed by hypoxia q12 h for 5d. Inactivated DNase1 and DNase1 were administered intraperitoneally twice daily in the control and treatment groups, respectively, starting on day 5 for 72 h. Survival, NEC score, intestinal damage (Chiu score, malondialdehyde [MDA], glutathione peroxidase [GPx]), inflammation (neutrophil elastase [NE], myeloperoxidase [MPO], toll-like receptor 4 [TLR4]), and NETs markers (SYTOX orange, cell-free DNA [cfDNA], DNase, citrullinated Histone 3 [H3cit]) were then assessed.

RESULTS

In total, 44 neonatal mice were used in the experiment. Mice in the treatment group demonstrated significantly reduced NEC rates (44 versus 86%, P = 0.029) and improved survival in comparison to controls (65 versus 35%, P = 0.01). Furthermore, mice treated with DNase1 showed significantly less tissue damage (cfDNA, Chiu score), oxidative stress (MDA, GPx), and inflammation (NE, MPO, H3cit, TLR4), which ultimately lead to a significant reduction in mortality.

CONCLUSIONS

The results of the study indicate that systemic DNase1 treatment leads to a significant reduction in tissue damage, NEC severity, and mortality. Therefore, after validation of our findings in human subjects, DNase1 treatment should be considered as a therapeutic option in neonates diagnosed with NEC.

Intestinal tight junctions are severely altered in NEC preterm neonates

BACKGROUND & AIMS

Necrotizing Enterocolitis (NEC) is a severe inflammatory disorder of the intestine endangering the health and survival of preterm infants. It is well established that the gut barrier is severely damaged in NEC patients, nonetheless an in depth investigation of modifications at the transcriptional and translational levels of tight junction genes and proteins during NEC are still missing. The aim of this study was to investigate changes in the expression of tight junctions and other associated proteins during NEC and determine their correlation to the disease severity.

METHODS

We examined intestinal specimens from six NEC patients and compared them with six control specimens from patients that underwent surgeries for reasons other than NEC. The expression of genes was analyzed by real time PCR and protein expression by immunohistochemistry.

RESULTS

The tight junction genes ZO-1, occludin, cingulin and claudin-4 were significantly down regulated in NEC. Furthermore TLR4, BAX and SIRT1 genes were found to be significantly down regulated while HIF-1A showed a trend of up regulation in NEC patients. These changes were found to correlate with the severity of the disease. Additionally we demonstrated in an ex-vivo model that hypoxic conditions initiated a destructive process of the epithelial barrier. We also showed that the expression of the tight junction proteins ZO-1 and occludin were significantly down regulated in NEC specimens.

CONCLUSIONS

The expression of tight junction proteins and their encoding genes are significantly altered in NEC. We surmise that SIRT1 and HIF-1A may play a role in controlling these effects.

Nutrition Management of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is one of the most significant causes of morbidity and mortality among premature infants. The exact cause is considered multifactorial and related to gastrointestinal immaturity, inflammation and enteral feeding. The role of nutrition is vitally important in NEC. The main modifiable risk factor is the introduction and advancement of enteral feedings. After an infant has recovered from NEC, enteral feeds should be cautiously resumed to prevent injury from prolonged use of parenteral nutrition. The logistics of how, when, and what to feed are somewhat unclear and often depend on the severity of the disease. For patients with an enterostomy, refeeding the distal intestine with the small-intestinal ostomy output may improve bowel growth and prevent long-term complications.

There is an association between disease location and gestational age at birth in newborns submitted to surgery due to necrotizing enterocolitis

OBJECTIVES

To evaluate if there are differences regarding disease location and mortality of necrotizing enterocolitis, according to the gestational age at birth, in newborns submitted to surgery due to enterocolite.

METHODS

A historical cohort study of 198 newborns submitted to surgery due to necrotizing enterecolitis in a tertiary hospital, from November 1991 to December 2012. The newborns were divided into different categories according to gestational age (<30 weeks, 30-33 weeks and 6 days, 34-36 weeks and 6 days, and ≥37 weeks), and were followed for 60 days after surgery. The inclusion criterion was the presence of histological findings of necrotizing enterocolitis in the pathology. Patients with single intestinal perforation were excluded.

RESULTS

The jejunum was the most commonly affected site in extremely premature infants (p=0.01), whereas the ileum was the most commonly affected site in premature infants (p=0.002), and the colon in infants born at term (p<0.001). With the increasing gestational age, it was observed that intestinal involvement decreased for the ileum and the jejunum (decreasing from 45% to 0% and from 5% to 0%, respectively), with a progressive increase in colon involvement (0% to 84%). Total mortality rate was 45.5%, and no statistical difference was observed in the mortality at different gestational ages (p=0.287).

CONCLUSIONS

In newborns submitted to surgery due to necrotizing enterocolitis, the disease in extremely preterm infants was more common in the jejunum, whereas in preterm infants, the most affected site was the ileum, and in newborns born close to term, it was the colon. No difference in mortality was observed according to the gestational age at birth.

Antenatal corticosteroids for women at risk of imminent preterm birth in low-resource countries: the case for equipoise and the need for efficacy trials

The scientific basis for antenatal corticosteroids (ACS) for women at risk of preterm birth has rapidly changed in recent years. Two landmark trials—the Antenatal Corticosteroid Trial and the Antenatal Late Preterm Steroids Trial—have challenged the long-held assumptions on the comparative health benefits and harms regarding the use of ACS for preterm birth across all levels of care and contexts, including resource-limited settings. Researchers, clinicians, programme managers, policymakers and donors working in low-income and middle-income countries now face challenging questions of whether, where and how ACS can be used to optimise outcomes for both women and preterm newborns.

In this article, we briefly present an appraisal of the current evidence around ACS, how these findings informed WHO’s current recommendations on ACS use, and the knowledge gaps that have emerged in the light of new trial evidence. Critical considerations in the generalisability of the available evidence demonstrate that a true state of clinical equipoise exists for this treatment option in low-resource settings. An expert group convened by WHO concluded that there is a clear need for more efficacy trials of ACS in these settings to inform clinical practice.