Evidence-based feeding strategies before and after the development of necrotizing enterocolitis

Oral administration of bone marrow-derived mesenchymal stem cells attenuates intestinal injury in necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is a major cause of morbidity in premature infants. However, effective treatment options for NEC are currently lacking.

PURPOSE

This study aimed to determine the optimal dose of intraperitoneally administered bone marrow-derived mesenchymal stem cells (BM-MSCs) and investigate the therapeutic potential of orally administered BM-MSCs in NEC.

METHODS

Neonatal mice were fed maternal breast milk for the first 2 days of life. On day 3, the neonatal mice were randomly divided into control, negative control, and BM-MSC-treated groups. Lipopolysaccharide (LPS) was administered for 3 days, and cold stress (4°C, 10 minutes) was applied 3 times a day to induce NEC. High-dose (1×106 cells) or low-dose (1×105 cells) BM-MSCs were administered intraperitoneally 1 or 3 times between days 6 and 8 to treat the NEC. The orally administered group received a low dose of BM-MSCs on day 6. Furthermore, except for the control group, intraepithelial cells (IECs) of the small intestine of neonatal mice were treated with LPS and exposed to 5% O2/95% N2 hypoxic stress for 2 hours. Thereafter, each was treated with BM-MSCs.

RESULTS

Tissue injury, apoptosis, and inflammatory marker levels were significantly reduced after BM-MSC administration. Oral administration was as effective as intraperitoneal administration, even at a low dose (1×105 cells) of BM-MSCs. The efficacy of high (1×106 cells) or multiple divided doses of BM-MSCs did not differ from that of low-dose treatment. Significantly improved wound healing was observed after BM-MSC administration to injured IECs.

CONCLUSION

The oral administration of BM-MSCs is a promising treatment option for NEC in infants. Further human studies of BM-MSCs are necessary to determine the optimal dose required to achieve safe and effective outcomes.

Vegan/vegetarian diet and human milk donation: An EMBA survey across European milk banks

The nutritional adequacy of human milk (HM) from vegan/vegetarian mothers has been a matter of debate, and a variety of recommendations regarding the eligibility of these mothers as human milk donors exists. According to the latest evidence, HM from vegans/vegetarians is similar in its composition to that from omnivores, however, some differences may be observed regarding vitamin B12 and omega-3 fatty acids concentrations. Maternal supplementation of these compounds has been proven effective in increasing their HM concentration. With this survey, we aimed to explore the practices currently in use in European human milk banks (HMBs) regarding potential donors following vegan/vegetarian diets. The online survey was distributed to European HMBs between January and July 2022. A total of 188 HMBs were contacted, and 118 replied (response rate 63%). Vegan and vegetarian mothers were recommended supplements of vitamin B12 to be accepted as donors in 27% and 26% of HMBs, respectively. Additional omega-3 fatty acid supplementation was required in 8% HMBs. In the remaining HMBs, these mothers were either systematically excluded or included regardless of supplementation. The dosage of the recommended supplements was extremely variable. Fifty-one percent of HMBs were following recommendations to guide their practice, national or local recommendations mainly. Great variability in European HMBs practices towards potential donors following vegan/vegetarian diets exists. Some of these practices can result in loss of donors and/or in potential nutritional deficiencies. Standardised evidence-based recommendations on this issue and their implementation in daily HMB practice are needed.

Twinning as a risk factor for neonatal acute intestinal diseases: a case-control study

Introduction

Acute intestinal diseases (AID), including necrotizing enterocolitis and spontaneous intestinal perforation, are a group of conditions that typically present in preterm infants, and are associated with an elevated mortality and morbidity rate. The risk factors for these diseases remain largely unknown. The aim of the study is to identify the correlation between twinning and the development of AID.

Methods

A single-center retrospective case-control study was conducted. We recruited all infants with a diagnosis of AID, confirmed by anatomopathology, recovered in NICU between 2010 and 2020. Considering the rarity of the outcome, 4 matched controls for each subject were randomly chosen from the overall population of newborns. Odds Ratio (OR) and 95% Confidence Interval (CI) were calculated using a conditional logistic regression model and a multivariate model by the creation of a Directed Acyclic Graph (www.dagitty.net).

Results

The study population resulted in 65 cases and 260 controls. The two groups present similar median gestational age and mean birthweight in grams. The cases have a higher frequency of neonatal pathology (defined as at least one of patent ductus arteriosus, early or late sepsis, severe respiratory distress) (84.6% vs. 51.9%), medically assisted procreation (33.8% vs. 18.8%) and periventricular leukomalacia (10.8% vs. 2.7%), and a lower frequency of steroids prophylaxis (67.7% vs. 86.9%). About 50% of cases needed surgery. The OR for the direct effect were difference from one using logistic regression booth without and with repeated measures statements: from 1.14 to 4.21 (p = .019) and from 1.16 to 4.29 (p = .016), respectively.

Conclusions

Our study suggests that twinning may be a risk factor for the development of AID. Due to the small number of cases observed, further studies on larger populations are needed.

Predictive Factors for Mortality in Pre-Term Neonates with Necrotizing Enterocolitis: A Retrospective Cohort Study

Background: Necrotizing enterocolitis (NEC) is a serious neonatal condition. Over the last three decades, there has been progress in neonatal intensive care with an increase in the incidence of pre-term births. This has led to an increase in the incidence of NEC. However, research studies regarding NEC outcomes in low-income countries are scarce. Our study aimed to assess predictive factors for mortality in patients with NEC in a single center in Tunisia. Patients and Methods: We conducted a retrospective data collection through a review of the patients' medical records. All neonates with a medical or surgical management of NEC between January 1, 2010 and March 31, 2022 were included. Results: A total of 102 neonates were included with the overall survival of 47%. Outcomes of the univariable analysis showed that patients in the deceased group had lower gestational age, lower five-minute Apgar score, lower birth weight, and lower platelet count than those in the survivor group. Multivariable logistic analyses demonstrated that gestational age <32 weeks (p = 0.024; odds ratio [OR], 2.5), five-minute Apgar score <8 (p = 0.017; OR, 3.621), birth weight <1,500 g (p = 0.001; OR, 4.136), platelet count <50,000/mm³ (p = 0.029; OR, 2.5), Bell's stage 3 (p = 0.035; OR, 2.496), and sepsis during hospitalization (p < 0.001; OR, 5.971) were associated with mortality in neonates with NEC. Conclusions: Our study showed that gestational age <32 weeks, five-minute Apgar score <8, very low birth weight, severe thrombocytopenia, Bell's stage 3, and sepsis during hospitalization were predictive factors for mortality in neonates with NEC. These factors would be useful to refine treatment modalities for better disease outcomes.

Dilemmas in initiation of very preterm infant enteral feeds-when, what, how?

With limited clinical evidence available to guide common nutritional decisions, significant variation exists in approaches to enteral feeding for very preterm infants, specifically when feedings are initiated, what is fed, and the method used for feedings. Preclinical studies have highlighted the benefits associated with avoiding nil per os and providing early-stage mother's own milk or colostrum. However, these recommended approaches are often mutually exclusive due to the delays in lactation associated with very preterm delivery, resulting in uncertainty regarding which approach should be prioritized. Few studies have evaluated feeding frequency in preterm infants, with limited generalizability to extremely preterm infants. Therefore, even evidence-based approaches to very preterm infant feed initiation can differ. Future research is needed to identify optimal strategies for enteral nutrition in very preterm infants, but, until then, evidence-informed approaches may vary depending on each neonatal intensive care unit's assessment of risk and benefit.

CCL3 aggravates intestinal damage in NEC by promoting macrophage chemotaxis and M1 macrophage polarization

BACKGROUND

NEC is a life-threatening gastrointestinal disease in neonates, the pathogenesis of which remains poorly understood.

METHODS

CCL3 levels in intestinal tissue of mice were measured and analyzed. HE staining was used to assess pathological changes in intestinal tissue. FCM was used to detect the proportion and phenotype of macrophages. RNA-seq and RT-PCR were used to evaluate the effect of CCL3 on macrophages.

RESULTS

CCL3 was highly expressed in the intestinal tissues of mice with NEC and induced macrophage infiltration. Transcriptome data showed that CCL3 strongly induced a transition in the phenotype of macrophages into a proinflammatory one. Mechanistically, in vivo experiments confirmed that CCL3 induced M1 macrophage polarization in NEC intestinal tissue, thereby aggravating inflammatory injury of intestinal tissue, which was alleviated by anti-CCL3 treatment. In addition, in vitro experiments showed that CCL3 significantly enhances the expression of M1-related genes in both PMφ and BMDM while inhibiting the expression of M2-related genes, which was also alleviated by anti-CCl3 treatment.

CONCLUSIONS

Our data elucidated the involvement of CCL3 in the pathogenesis of NEC, in which upregulated CCL3 expression exacerbated inflammatory intestinal damage by regulating macrophage chemotaxis and M1 phenotype polarization, suggesting that blocking CCL3 may be a potential strategy for effective intervention in NEC.

IMPACT

Our study represents an important conceptual advancement that CCL3 may be one of the key culprits of intestinal tissue damage in patients with NEC. CCL3 aggravates inflammatory intestinal injury and intestinal mucosal barrier imbalance by regulating the chemotaxis, polarization, and function of macrophages. Blocking CCL3 significantly reduced NEC-mediated intestinal injury, suggesting a new potential therapeutic strategy.

Variability in antibiotic duration for necrotizing enterocolitis and outcomes in a large multicenter cohort

OBJECTIVES

To evaluate variability in antibiotic duration for necrotizing enterocolitis (NEC) and associated clinical outcomes.

STUDY DESIGN

Five-hundred ninety-one infants with NEC (315 medical; 276 surgical) were included from 22 centers participating in Children's Hospitals Neonatal Consortium (CHNC). Multivariable analyses were used to determine predictors of variability in time to full feeds (TFF) and length of stay (LOS).

RESULTS

Median (IQR) antibiotic duration was 12 (9, 17) days for medical and 17 (14, 21) days for surgical NEC. Wide variability in antibiotic use existed both within and among centers. Duration of antibiotic therapy was associated with longer TFF in both medical (OR 1.04, 95% CI [1.01, 1.05], p < 0.001) and surgical NEC (OR 1.02 [1, 1.03] p = 0.046); and with longer LOS in medical (OR 1.03 [1.02, 1.04], p < 0.001) and surgical NEC (OR 1.01 [1.01, 1.02], p = 0.002).

CONCLUSION

Antibiotic duration for both medical and surgical NEC remains variable within and among high level NICUs.

The role of ultrasound in necrotizing enterocolitis

Ultrasound has proved to be a useful modality for enhancing the diagnostic accuracy of necrotizing enterocolitis and associated complications. The standard imaging algorithm for evaluating necrotizing enterocolitis includes radiographs and clinical symptoms, the combination of which constitutes the Bell criteria. Major limitations of using the Bell criteria for diagnosing and clinically managing necrotizing enterocolitis include low diagnostic accuracy of radiographs and nonspecific symptomatology of preterm infants. In this regard, US can offer additional insights into bowel health by helping to characterize bowel motility, echogenicity, thickness, pneumatosis and perfusion. Extramural findings such as portal venous gas, nature and extent of ascites, and pneumoperitoneum can also be assessed. Recently, contrast-enhanced US was explored in a case series of preterm bowel disease and its diagnostic utility warrants further investigation. This article reviews the US features of necrotizing enterocolitis and highlights the role of US as a complement to radiographs, as well as the emerging use of contrast-enhanced US in necrotizing enterocolitis.

Beneficial Effects of Bovine Milk Exosomes in Metabolic Interorgan Cross-Talk

Extracellular vesicles are membrane-enclosed secreted vesicles involved in cell-to-cell communication processes, identified in virtually all body fluids. Among extracellular vesicles, exosomes have gained increasing attention in recent years as they have unique biological origins and deliver different cargos, such as nucleic acids, proteins, and lipids, which might mediate various health processes. In particular, milk-derived exosomes are proposed as bioactive compounds of breast milk, which have been reported to resist gastric digestion and reach systemic circulation, thus being bioavailable after oral intake. In the present manuscript, we critically discuss the available evidence on the health benefits attributed to milk exosomes, and we provide an outlook for the potential future uses of these compounds. The use of milk exosomes as bioactive ingredients represents a novel avenue to explore in the context of human nutrition, and they might exert important beneficial effects at multiple levels, including but not limited to intestinal health, bone and muscle metabolism, immunity, modulation of the microbiota, growth, and development.

The role of feeding advancement strategy on length of stay and hospital costs in newborns with gastroschisis

BACKGROUND

Infants with gastroschisis require prolonged hospitalization for surgical repair and gradual advancement of feeds. The present study explores the effect of a change in a protocolized enteral feeding regimen with length of hospital stay (LOS) and total costs in newborns with gastroschisis.

METHODS

A retrospective review was performed in neonates with uncomplicated gastroschisis at a free-standing pediatric institution from 2012 to 2020. The effect of two different enteral feed advancement protocols on clinical outcomes and hospital costs was analyzed.

RESULTS

Seventy-four patients were identified, of which 50 (68%) underwent 10 ml/kg/day feeding advancements, and 24 (32%) underwent 20 ml/kg/day feeding advancements. Compared to neonates who underwent 10 ml/kg/day enteral advancements, neonates receiving 20 ml/kg/day advancements reached goal feeds faster (14 vs 20 days, p<0.001), were younger at goal feeds (26 vs 34 days, p = 0.001), required fewer days of parenteral nutrition (22 vs 29 days, p = 0.001), and had shorter LOS (30 vs 36 days, p = 0.001). On multivariable analysis, total costs decreased by 9.77% in the 20 ml/kg/day advancement cohort (p = 0.071).

CONCLUSION

In neonates with uncomplicated gastroschisis who underwent primary repair, a nutritional protocol that incorporated 20 ml/kg/day feeding advancements was safe and resulted in faster attainment of goal feeds and shorter LOS.

LEVEL OF EVIDENCE

II/III.

Making Research Flourish Through ESPGHAN: A Position Paper From the ESPGHAN Special Interest Group for Basic and Translational Research

ABSTRACT

Recent research breakthroughs have emerged from applied basic research throughout all scientific areas, including adult and paediatric gastroenterology, hepatology and nutrition (PGHAN). The research landscape within the European Society of Paediatric Gastroenterology and Nutrition (ESPGHAN) is also inevitably changing from clinical research to studies involving applied laboratory research. This position paper aims to depict the current status quo of basic science and translational research within ESPGHAN, and to delineate how the society could invest in research in the present and future time. The paper also explores which research areas in the field of PGHAN represent the current and future priorities, and what type of support is needed across the ESPGHAN working groups (WGs) and special interest groups (SIGs) to fulfil their research goals.

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.

Impact of Docosahexaenoic acid supplementation on proinflammatory cytokines release and the development of Necrotizing enterocolitis in preterm Neonates: A randomized controlled study

INTRODUCTION

Preterm neonates have under-developed immune-regulatory system; consequently, there is a risk for developing chronic inflammation. Necrotizing enterocolitis (NEC) is an acute devastating neonatal intestinal inflammatory disorder. Due to the obscure multifactorial etiology, early diagnosis and effective treatment of NEC are limited. Consequently, effective strategies in the prevention of NEC, including nutritional approaches, are critically needed. The current study was conducted to assess the potential immunomodulatory effect of Docosahexaenoic Acid (DHA) supplementation in preterm neonates at neonatal intensive care unit (NICU) and subsequently its effect on preventing or reducing NEC incidence.

METHODS

This was a prospective randomized controlled study. A total of 67 neonates, with gestational age equal or less than 32 weeks at birth and weight less than or equal 1500 g, were randomly assigned to either DHA group or the control group. Modified Bell's staging criteria for NEC was used as an objective tool for diagnosis and staging of NEC. Levels of Interleukin 1 beta (IL-1β) were measured at baseline and after 10 days. Mortality and NICU length of stay (LOS) were also monitored.

RESULTS

Thirty neonates of each group completed the study. A statistically significant difference was observed between the two groups regarding diagnosis and staging of NEC (p = 0.0001). There was also a statistically significant difference between DHA group 22(73.3), 95% CI [55.9, 86.5] and the control group 8 (26.7), 95% CI [13.5, 44.1] in the percentage change in IL-1β levels (p = 0.0001).A statistically significant association was found between IL and 1 β change and NEC diagnosis (p = 0.001). NICU LOS was significantly lower among DHA group 21.63 ± 6.67 compared to the control group 25.07 ± 4.67 (p = 0.025). Mortality n (%) among the control group 4 (11.8) was higher than DHA group 3 (9.1), however, no significant difference was detected (p = 1.0).

CONCLUSION

Findings of this study suggest that enteral DHA supplementation can reduce NEC incidence in preterm neonates through its immunoregulatory effect that modulates production of regulatory cytokines.Trial registration: Registered at clinical trials.gov (NCT03700957), 6 October 2018.

Outcomes improved with human milk intake in preterm and full-term infants

This review highlights clinical outcomes of human milk from infancy through adulthood. Human milk outcomes of both preterm and term infants, including critically ill term infants (such as infants with congenital heart disease and those requiring therapeutic hypothermia) are summarized. Several human milk diets are identified to reduce the risk of specific diseases. Emerging research of newly discovered components of human milk are also reviewed. Human milk has significant effects on the gut microbiome, somatic growth, and neurocognitive outcomes. Continued research promises to improve donor human milk and donor milk derived products to achieve better outcomes for infants who do not receive their own mother's milk. The promotion of human milk is well-founded on evidence from the previous half century.

A Mouse Model of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is an acute inflammatory disease that unforeseeably develops in very low birth weight premature infants. NEC is characterized by impairment of the intestinal barrier resulting in intestinal necrosis and multisystem organ failure. Animal models of NEC have contributed significantly to a better understanding of the underlying molecular mechanisms of the disease and facilitated the exploration of potential new therapeutic strategies. Here, we provide a detailed protocol that recapitulates some of the main histological and transcriptional features of human NEC in newborn mice.

Gut transit time, using radiological contrast imaging, to predict early signs of necrotizing enterocolitis

BACKGROUND

Immature gut motility in preterm neonates may be a risk factor for necrotizing enterocolitis (NEC). Using preterm pigs as a model for infants, we hypothesized that intestinal dysmotility precedes NEC development.

METHODS

Eighty-five preterm pigs were fed increasing amounts of milk diets to induce NEC lesions, as detected at autopsy on day 5. Gut transit time was determined on day 4 by x-ray imaging after oral intake of contrast solution.

RESULTS

No clinical or radiological signs of NEC were detected on day 4, but macroscopic NEC lesions were recorded in 59% of pigs (n = 50) on day 5. Relative to pigs without NEC (noNEC, n = 35), pigs with small intestinal lesions (siNEC, n = 18) showed delayed stomach emptying time (StEmpty) and time for contrast to reach cecum (ToCecum) already on day 4. Pigs with lesions only in colon (coNEC, n = 20) showed more diarrhea, shorter ToCecum time, but longer small intestinal emptying time (SiEmpty). ToCecum time predicted siNEC and coNEC lesions with a receiver-operator characteristic area under the curve of 78-81%.

CONCLUSIONS

Region-dependent changes in gut transit time is associated with early NEC development in preterm pigs. How gut dysmotility is related to NEC in preterm infants requires further investigations.

IMPACT

Using preterm pigs as a model for preterm infants, we show that gut transit time, using serial x-ray contrast imaging, was changed in individuals with NEC-like lesions before they showed the typical radiological signs of NEC. Thus prolonged transit time across the entire gut was recorded when NEC lesions appeared in the small intestine but not when lesions were detected only in the colon. Until now, recordings of food transit have mainly investigated changes in the upper gut. Using serial x-rays, this study describes food transit across the entire gut and documents a region-dependent effect of NEC lesions on gut transit changes in preterm individuals. The findings provide proof of concept for use of x-ray contrast imaging as a tool to monitor gut transit in preterm pigs as models for infants. Delayed passage across the entire gut may be an early sign of small intestinal NEC, at least in pigs. More studies are needed to confirm relations in infants. In the future, it might be possible to use x-ray contrast imaging in preterm infants to better understand gut motility in relation to early NEC progression and need for medical NEC treatment.

Bolus versus continuous feedings following treatment for medical necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is a serious, often fatal, disease of neonates. Minimal data exists regarding the optimal method for reintroducing feeds after successful treatment. This study aims to compare outcomes in patients reintroduced to bolus or continuous feeds after treatment for medical NEC.

METHODS

A retrospective review of infants treated for medical NEC in the neonatal intensive care unit (NICU) from 2011-2018 was performed. Demographics, information about initial feeds, clinical diagnosis data, and information about reintroduction of feeds were recorded. Patients with significant congenital heart disease or those who required procedures for treatment were excluded.

RESULTS

Sixty-one patients were analyzed; 45 were reintroduced to bolus feeds and 16 to continuous feeds. There were no differences between the two groups. Bolus-fed patients reached goal feeds quicker (p = 0.007), required fewer days of parenteral nutrition (p = 0.002), had shorter hospital stays (p = 0.013) and were discharged faster from diagnosis to discharge (p = 0.002). Differences were confirmed with multivariate regression.

CONCLUSION

Infants given bolus feeds reached goal feeds faster, required less time on PN, and were discharged quicker than those fed continuously. This suggests that, compared to continuous feeding, bolus feeding is associated with superior clinical outcomes among patients treated for medical NEC.

Hope on the horizon: promising novel therapies for necrotizing enterocolitis

Necrotizing enterocolitis (NEC) remains among the most common and devastating diseases in neonates. Despite advances in neonatal clinical care, specific treatment strategies and diagnostic modalities remain lacking. As a result, morbidity and mortality remain high. Improved understanding of the pathogenesis of NEC has the potential for improved therapeutics. Some of the areas of research leading to promising discoveries include inhibition of Toll-like receptor signaling, modulation of vascular endothelial growth factor signal pathways, defining metabolomic alterations in NEC to discover potential biomarkers, probing for genetic predispositions to NEC susceptibility, determining mechanistic relations between anemia and NEC, and microflora modulation through the use of probiotics. All of these areas may represent novel promising approaches to the prevention and treatment of NEC. This review will focus on these current and possible therapeutic perspectives.

Developmental 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure of either parent enhances the risk of necrotizing enterocolitis in neonatal mice

BACKGROUND

Necrotizing enterocolitis (NEC) is a rare, but potentially fatal intestinal inflammatory condition most often arising in premature infants. Infants provided formula are also at greater risk of developing this disease. Although the majority of formula-fed, preterm infants do not develop NEC, up to 30% of infants with the disease do not survive. Thus, identifying additional, currently unrecognized factors, which may predispose a specific infant to NEC development would be a significant clinical advancement. In this regard, we have previously reported that offspring of female or male mice with a history of developmental exposure to the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exhibit altered sensitivity to inflammatory challenges and are frequently born premature. Herein, we examined the possibility that, compared to unexposed mice (F1_NONE ), developmental TCDD exposure of either parent (maternal, F1M_TCDD , or paternal, F1P_TCDD ) would enhance the risk of NEC in offspring (F2_TCDD mice) in association with supplemental formula feeding.

METHODS

Beginning on postnatal day 7, all neonates were randomized to maternal milk only or maternal milk with up to 20 supplemental formula feedings. All pups remained with the Dams and were additionally allowed to nurse ad libitum.

RESULTS

Formula-fed F2_NONE pups rarely developed NEC while this disease was common in formula-fed F2M_TCDD and F2P_TCDD mice. Unexpectedly, 50% of F2M_TCDD pups that were not provided supplemental formula also developed NEC.

CONCLUSIONS

Our studies provide evidence that a history of parental TCDD exposure enhances the risk of NEC in offspring and suggest exposure to environmental immunotoxicants such as TCDD may also contribute to this inflammatory disease in humans.

An exclusive human milk diet for very low birth weight newborns-A cost-effectiveness and EVPI study for Germany

OBJECTIVES

Human milk-based fortifiers have shown a protective effect on major complications for very low birth weight newborns. The current study aimed to estimate the cost-effectiveness of an exclusive human milk diet (EHMD) compared to the current approach using cow's milk-based fortifiers in very low birth weight newborns.

METHODS

A decision tree model using the health states of necrotising enterocolitis (NEC), sepsis, NEC + sepsis and no complication was used to calculate the cost-effectiveness of an EHMD. For each health state, bronchopulmonary dysplasia (BPD), retinopathy of prematurity (RoP) and neurodevelopmental problems were included as possible complications; additionally, short-bowel syndrome (SBS) was included as a complication for surgical treatment of NEC. The model was stratified into birth weight categories. Costs for inpatient treatment and long-term consequences were considered from a third party payer perspective for the reference year 2017. Deterministic and probabilistic sensitivity analyses were performed, including a societal perspective, discounting rate and all input parameter-values.

RESULTS

In the base case, the EHMD was estimated to be cost-effective compared to the current nutrition for very low birth weight newborns with an incremental cost-effectiveness ratio (ICER) of €28,325 per Life-Year-Gained (LYG). From a societal perspective, the ICER is €27,494/LYG using a friction cost approach and €16,112/LYG using a human capital approach. Deterministic sensitivity analyses demonstrated that the estimate was robust against changes in the input parameters and probabilistic sensitivity analysis suggested that the probability EHMD was cost-effective at a threshold of €45,790/LYG was 94.8 percent.

CONCLUSION

Adopting EHMD as the standard approach to nutrition is a cost-effective intervention for very low birth weight newborns in Germany.

A Novel Role for Necroptosis in the Pathogenesis of Necrotizing Enterocolitis

BACKGROUND & AIMS

Necrotizing enterocolitis (NEC) is a devastating disease of premature infants characterized by Toll-like receptor 4 (TLR4)-dependent intestinal inflammation and enterocyte death. Given that necroptosis is a proinflammatory cell death process that is linked to bacterial signaling, we investigated its potential role in NEC, and the mechanisms involved.

METHODS

Human and mouse NEC intestine were analyzed for necroptosis gene expression (ie, RIPK1, RIPK3, and MLKL), and protein activation (phosphorylated RIPK3). To evaluate a potential role for necroptosis in NEC, the effects of genetic (ie, Ripk3 knockout or Mlkl knockout) or pharmacologic (ie, Nec1s) inhibition of intestinal inflammation were assessed in a mouse NEC model, and a possible upstream role of TLR4 was assessed in Tlr4-deficient mice. The NEC-protective effects of human breast milk and its constituent milk oligosaccharides on necroptosis were assessed in a NEC-in-a-dish model, in which mouse intestinal organoids were cultured as either undifferentiated or differentiated epithelium in the presence of NEC bacteria and hypoxia.

RESULTS

Necroptosis was activated in the intestines of human and mouse NEC in a TLR4-dependent manner, and was up-regulated specifically in differentiated epithelium of the immature ileum. Inhibition of necroptosis genetically and pharmacologically reduced intestinal-epithelial cell death and mucosal inflammation in experimental NEC, and ex vivo in the NEC-in-a-dish system. Strikingly, the addition of human breast milk, or the human milk oligosaccharide 2 fucosyllactose in the ex vivo system, reduced necroptosis and inflammation.

CONCLUSIONS

Necroptosis is activated in the intestinal epithelium upon TLR4 signaling and is required for NEC development, and explains in part the protective effects of breast milk.

Recent Advances in Prevention and Therapies for Clinical or Experimental Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is one of the most severe diseases of preterm neonates and has a high mortality rate. With the development of inspection techniques and new biomarkers, the diagnostic accuracy of NEC is constantly improving. The most recognized potential risk factors include prematurity, formula-feeding, infection, and microbial dysbiosis. With further understanding of the pathogenesis, more effective prevention and therapies will be applied to clinical or experimental NEC. At present, such new potential prevention and therapies for NEC are mainly focused on the Toll-like receptor 4 inflammatory signaling pathway, the repair of intestinal barrier function, probiotics, antioxidative stress, breast-feeding, and immunomodulatory agents. Many new studies have changed our understanding of the pathogenesis of NEC and improve our approaches for preventing and treating of NEC each year. This review provides an overview of the recent researches focused on clinical or experimental NEC and highlights the advances made within the past 5 years toward the development of new potential preventive approaches and therapies for this disease.

Fat composition in infant formula contributes to the severity of necrotising enterocolitis

Necrotising enterocolitis (NEC) is a devastating disease that typically affects formula-fed premature infants, suggesting that dietary components may influence disease pathogenesis. TAG are the major fat components of infant formula, and their digestion requires pancreatic lipases, which may be naturally deficient in premature neonates. We hypothesise that NEC develops partly from the accumulation of incompletely digested long-chain TAG-containing unsaturated fatty acids within the intestinal epithelial cells, leading to oxidative stress and enterocyte damage. We further hypothesise that the administration of a formula that contains reduced TAG ('pre-digested fat') that do not require lipase action may reduce NEC severity. To test these hypotheses, we induced NEC in neonatal mice using three different fat formulations, namely 'standard fat', 'pre-digested fat' or 'very low fat', and determined that mice fed 'standard fat' developed severe NEC, which was significantly reduced in mice fed 'pre-digested fat' or 'very low fat'. The expression level of the critical fat-digesting enzyme carboxyl ester lipase was significantly lower in the newborn compared with older pups, leading to impaired fat digestion. The accumulation of mal-digested fat resulted in the significant accumulation of fat droplets within the intestinal epithelium of the distal ileum, resulting in the generation of reactive oxygen species and intestinal inflammation. Strikingly, these changes were prevented in pups fed 'pre-digested fat' or 'very low fat' formulas. These findings suggest that nutritional formula containing a pre-digested fat system may overcome the natural lipase deficiency of the premature gut, and serve as a novel approach to prevent NEC.

Recent Potential Noninvasive Biomarkers in Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a rare but devastating gastrointestinal disease that predominately affects preterm neonates. Numerous studies have revealed that NEC is strongly associated with very low birth weight, degree of prematurity, formula feeding, infection, hypoxic/ischemic injury, and enteric dysbiosis. Given these clinical associations, the search for a deeper understanding of disease pathogenesis has led to an intense interest in the discovery and development of noninvasive biomarkers of NEC from stool, urine, and serum. Biomarkers for NEC may serve at least two general purposes of urgent unmet need: to improve diagnostic accuracy and disease prediction and to reveal the mechanism of the disease. This review will provide an overview of recent research focused on clinical NEC and highlight the advances that were made within the past five years towards the development of noninvasive diagnostic biomarkers.

Curcumin and Intestinal Inflammatory Diseases: Molecular Mechanisms of Protection

Intestinal inflammatory diseases, such as Crohn’s disease, ulcerative colitis, and necrotizing enterocolitis, are becoming increasingly prevalent. While knowledge of the pathogenesis of these related diseases is currently incomplete, each of these conditions is thought to involve a dysfunctional, or overstated, host immunological response to both bacteria and dietary antigens, resulting in unchecked intestinal inflammation and, often, alterations in the intestinal microbiome. This inflammation can result in an impaired intestinal barrier allowing for bacterial translocation, potentially resulting in systemic inflammation and, in severe cases, sepsis. Chronic inflammation of this nature, in the case of inflammatory bowel disease, can even spur cancer growth in the longer-term. Recent research has indicated certain natural products with anti-inflammatory properties, such as curcumin, can help tame the inflammation involved in intestinal inflammatory diseases, thus improving intestinal barrier function, and potentially, clinical outcomes. In this review, we explore the potential therapeutic properties of curcumin on intestinal inflammatory diseases, including its antimicrobial and immunomodulatory properties, as well as its potential to alter the intestinal microbiome. Curcumin may play a significant role in intestinal inflammatory disease treatment in the future, particularly as an adjuvant therapy.

Use of Breast Milk and Other Feeding Practices Following Gastrointestinal Surgery in Infants

OBJECTIVES

The aim of the study was to characterize the enteral feeding practices in infants after gastrointestinal surgery.

METHODS

We performed a retrospective analysis of infants who underwent intestinal surgery at age <6 months who survived to be fed enterally between January 2012 and June 2017. Demographics, surgical characteristics, feeding practices, and growth-related outcomes during hospitalization, discharge, and follow-up (3, 6, and 12 months) were obtained from the electronic medical records. Descriptive statistics compared infants by their initial diagnosis.

RESULTS

We reviewed 111 infants: necrotizing enterocolitis (NEC) = 21, gastroschisis = 28, atresia = 27, spontaneous intestinal perforation (SIP) = 18, and other diagnoses = 17. Most infants (77%) received mother's milk (MM) as the first postoperative feed, but this differed by diagnosis (P = 0.004). Donor milk was used in 11%, most commonly in infants with NEC and SIP. Infants with NEC were least likely to continue MM in the hospital (7%, P = 0.0014) and were more likely to receive elemental formula. Only 44% of infants received MM at discharge. After 1 year, 25% were fed MM. The majority of infants were discharged with feeding tubes (nasogastric: 35%, gastric: 23%). Although all groups had acceptable weights at discharge, infants with NEC (z score: -1.8) and SIP (z score: -1.1) showed growth failure at 3 months (z scores: -3.3, -3.2, respectively, P < 0.0001), but had appropriate gain by 1 year (z scores: -1.1, -1.7, respectively).

CONCLUSIONS

Despite most infants receiving MM in the early postoperative period, <50% at discharge and only 33% at 1-year still received MM. Weight gain after discharge in infants with NEC and SIP warrants close monitoring.

Time to reintroduction of feeding in infants with nonsurgical necrotizing enterocolitis

BACKGROUND

For infants with necrotizing enterocolitis (NEC) treated nonoperatively, no consensus exists on the optimal fasting period prior to reintroducing feeds after NEC. We report our experience with early (<7days) and late (≥7days) refeeding in this population.

METHODS

A chart review of infants with NEC born between 2006 and 2016 was performed. Data elements include demographics, comorbidities, day of diagnosis, Bell's stage, recurrence, strictures, length of stay and mortality, and were grouped into early and late refeeding. T-tests were used for means and chi-squared tests for distribution of proportions. Linear and logistic regressions were used to further evaluate the association of length of stay, stricture, recurrence, and death with time to refeeding.

RESULTS

Of 228 NEC patients, 149(65%) were treated nonoperatively (Bell Stages I, IIA, IIB, IIIA). Eleven patients were excluded owing to never restarting feeds, largely secondary to early death. The early (n=40) and late refeeding (n=98) groups were not significantly different with regard to mean gestational age at birth, race, birth weight, day of life at NEC diagnosis, or cardiac disease. NEC Stage was significantly different (p<0.001). The late group had significantly more Stage IIB patients (p=.02), and the early group had more stage I patients (p=<0.01). After adjusting for Bell's stage, the odds of NEC recurrence, death, and the composite outcome of recurrence or stricture or death were not significantly different between early and late groups.

CONCLUSIONS

No standardized guidelines exist for restarting enteral nutrition following medical NEC. In patients managed nonoperatively, early reintroduction of feeding was not significantly associated with increased NEC recurrence, mortality, or stricture.

LEVEL OF EVIDENCE

Treatment Study - Level III.

Evolving understanding of neonatal necrotizing enterocolitis

PURPOSE OF REVIEW

Necrotizing enterocolitis (NEC) is a devastating disease that predominately affects premature neonates. The pathogenesis of NEC is multifactorial and poorly understood. Risk factors include low birth weight, formula-feeding, hypoxic/ischemic insults, and microbial dysbiosis. This review focuses on our current understanding of the diagnosis, management, and pathogenesis of NEC.

RECENT FINDINGS

Recent findings identify specific mucosal cell types as potential therapeutic targets in NEC. Despite a broadly accepted view that bacterial colonization plays a key role in NEC, characteristics of bacterial populations associated with this disease remain elusive. The use of probiotics such as lactobacilli and bifidobacteria has been studied in numerous trials, but there is a lack of consensus regarding specific strains and dosing. Although growth factors found in breast milk such as epidermal growth factor and heparin-binding epidermal growth factor may be useful in disease prevention, developing new therapeutic interventions in NEC critically depends on better understanding of its pathogenesis.

SUMMARY

NEC is a leading cause of morbidity and mortality in premature neonates. Recent data confirm that growth factors and certain bacteria may offer protection against NEC. Further studies are needed to better understand the complex pathogenesis of NEC.

Toll-Like Receptor-Mediated Intestinal Inflammatory Imbalance in the Pathogenesis of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) remains the leading cause of death from gastrointestinal disease in premature infants and attacks the most fragile patients at a time when they appear to be the most stable. Despite significant advances in our overall care of the premature infant, NEC mortality remains stubbornly high. There is no specific treatment for NEC beyond broad-spectrum antibiotics and intestinal resection, and current efforts have focused on preventive strategies. Over the past decade, we have proposed a unifying hypothesis to explain the pathogenesis of NEC in premature infants that suggests that NEC develops in response to an imbalance between exaggerated proinflammatory signaling in the mucosa of the premature gut leading to mucosal injury, which is not countered effectively by endogenous repair processes, and in the setting of impaired mesenteric perfusion leads to intestinal ischemia and disease development. One of the most important pathways that mediates the balance between injury and repair in the premature intestine, and that plays a key role in NEC pathogenesis, is Toll-like receptor 4 (TLR4), which recognizes lipopolysaccharide on gram-negative bacteria. This review focuses on the role that the TLR4-mediated imbalance between proinflammatory and anti-inflammatory signaling in the premature intestinal epithelium leads to the development of NEC, and will explore how an understanding of the role of TLR4 in NEC pathogenesis has led to the identification of novel preventive or treatment approaches for this devastating disease.

Necrotizing enterocolitis: Pathophysiology from a historical context

Necrotizing enterocolitis (NEC) continues to afflict approximately 7% of preterm infants born weighing less than 1500g, though recent investigations have provided novel insights into the pathogenesis of this complex disease. The disease has been a major cause of morbidity and mortality in neonatal intensive care units worldwide for many years, and our current understanding reflects exceptional observations made decades ago. In this review, we will describe NEC from a historical context and summarize seminal findings that underscore the importance of enteral feeding, the gut microbiota, and intestinal inflammation in this complex pathophysiology.

Protective effects of amniotic fluid in the setting of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the most common life threatening condition affecting preterm infants. NEC occurs in 1-5% of all neonatal intensive care admissions and 5-10% of very low birth weight infants. The protective role of human breast milk (BM) has been well established. It has also been shown that amniotic fluid (AF) and BM have many similarities in terms of presence of growth and other immune-modulatory factors. This finding led to the initial hypothesis that AF may exert similar protective effects against the development of NEC, as does BM. Multiple studies have elucidated the presence of growth factors in AF and the protective effect of AF against NEC. Studies have also described possible mechanisms how AF protects against NEC. At present, research in this particular area is extremely active and robust. This review summarizes the various studies looking at the protective effects of AF against the development of NEC. It also provides an insight into future directions, the vast potential of AF as a readily available biologic medium, and the ethical barriers that must be overcome before using AF.

Necrotizing enterocolitis in premature infants and newborns

Necrotizing enterocolitis (NEC) is the most common acquired disease of the gastrointestinal tract (GIT) in premature infants and newborns. It is defined as an ulcerative inflammation of the intestinal wall. The clinical signs of incipient NEC are often very discrete, and range from localized intestinal symptoms to generalized signs of sepsis. NEC is classified depending on its severity into disease states according to the modified Bell's Classification. Treatment of NEC ranges, depending on its severity, from a conservative therapeutic approach to surgery with resection of the affected parts of the intestine. Mortality is considerably high in extremely small preterm infants reaching up to 42% of the affected children. Measures such as breastfeeding or alternatively nutrition with pasteurized human donor milk from a milk bank, administration of probiotics, avoidance of histamine type II receptor antagonists, and restrictive antibiotic treatment should be considered early on for prevention of NEC.

Efficient Fluorescence Detection of Aromatic Toxicants and Toxicant Metabolites in Human Breast Milk

Once chemical contaminants are released into the environment, there are a number of concerns that arise regarding the environmental persistence of the contaminants, their known and suspected toxicities, and their potential disruption to the ecosystem. One class of contaminants that is of continuing concern is polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants that are significant components of oil spills. PAHs have been found in the breast milk of nursing mothers living in oil spill affected regions, and can harm the nursing children. We report herein the sensitive and selective detection of 10 PAHs and PAH metabolites in human breast milk using fluorescence energy transfer from the PAH to a high quantum yield fluorophore, and array-based statistical analyses of the resulting fluorescence responses. This detection system was able to separate and identify the PAHs with 100% success in human breast milk and at concentrations as low as 0.17 μM. These results have significant implications in public health and in the monitoring and mitigation of environmental disasters.

Risk factors for necrotizing enterocolitis in neonates: a systematic review of prognostic studies

BACKGROUND

Necrotizing enterocolitis (NEC) is a severe multifactorial disease in preterm neonates associated with high morbidity and mortality. Better insight into prognostic values of the many reported factors associated with NEC is needed to enable identification of neonates at risk for NEC. The aim was to systematically review the literature to identify independent risk factors for NEC from the literature.

METHODS

Medline, Cochrane, Embase, Pubmed and Google Scholar were searched systematically for cohort studies reporting prognostic factors for NEC in neonates using multivariable analysis. Studies were scored with the Quality In Prognosis Studies tool (QUIPS).

RESULTS

From 5154 initial hits, 14 prognostic studies were included, with various designs. Study quality was rated high in three studies, moderate or low in the 11 others. Significant prognostic factors for NEC reported in at least two studies were: low birth weight, small for gestational age, low gestational age, assisted ventilation, premature rupture of membranes, black ethnicity, sepsis, outborn, hypotension (all increased risk), surfactant therapy (conflicting results) and cesarean section (lower risk). Meta-analysis was considered not feasible.

CONCLUSION

High quality studies on prognostic factors for NEC are rare. Several prognostic factors, that are not necessarily causal, are associated with NEC. High quality prognostic research is necessary to establish the predictive values of these factors.

Red blood cell transfusion in premature infants leads to worse necrotizing enterocolitis outcomes

BACKGROUND

Necrotizing enterocolitis (NEC) is a severe intestinal disease of premature infants with high mortality. Studies suggest a causative relationship between red blood cell (RBC) transfusion and NEC; however, whether RBC transfusion leads to worse outcomes in NEC is unknown. We sought to determine whether RBC transfusion was associated with an increased risk of surgical NEC and mortality.

METHODS

In this retrospective study, 115 patients were enrolled with NEC Bell's stage 2A or greater from 2010-2015. Patients were classified based on the timing of RBC transfusion before NEC: ≤72 h, >72 h, and no transfusion. Variables including gestational age (GA), birth weight (BW), feedings, and hematocrit levels were analyzed. Outcomes were surgical intervention for NEC following RBC transfusion and mortality.

RESULTS

Twenty-three (20%) infants developed NEC ≤ 72 h after RBC transfusion, 16 (69.6%) required surgery with a mortality rate of 21.7% (n = 5). Seventeen (15%) infants developed NEC > 72 h after RBC transfusion, 12 (70.6%) required surgery with a mortality rate of 23.5% (n = 4). 75 (65%) patients developed NEC without RBC transfusion, 17 (22.7%) required surgery with a mortality rate of 4% (n = 3). Lower GA and BW were significantly associated with RBC transfusion and the need for surgical intervention. RBC transfusion ≤72 h before NEC was associated with surgical NEC (pairwise adjusted P < 0.001) and mortality (pairwise adjusted P = 0.048). However, multivariable logistic regression analysis revealed RBC transfusion is not an independent risk factor for surgical NEC.

CONCLUSIONS

Infants of lower GA and BW were more likely to receive an RBC transfusion before NEC, which was significantly associated with surgical intervention and an increasing risk of mortality. Judicious use of transfusions in premature infants may improve NEC outcomes.

Pathogenesis of NEC: Impact of an altered intestinal microbiome

Necrotizing enterocolitis (NEC), a disease most commonly seen in preterm infants, often presents without warning and is associated with very high mortality and morbidity. Progress in the prevention and treatment of NEC has been slow. In this article, we will discuss some of the reasons as to why this progress has been slow. We will describe some of the factors that appear to be highly associated and important components in the pathophysiology of NEC. We will discuss the intestinal microbial environment of the fetus as well as the preterm infant and how interaction of dysbiosis with an immature gastrointestinal tract combined with dietary factors play a role in the pathogenesis of NEC. Testable hypotheses are discussed as well as how these may lead to not only a better understanding of the pathophysiology of the disease but also the preventative strategies.

Increased incidence of necrotizing enterocolitis in the Netherlands after implementation of the new Dutch guideline for active treatment in extremely preterm infants: Results from three academic referral centers

INTRODUCTION

Necrotizing enterocolitis (NEC) is a severe inflammatory disease, mostly occurring in preterm infants. The Dutch guidelines for active treatment of extremely preterm infants changed in 2006 from 26+0 to 25+0weeks of gestation, and in 2010 to 24+0 of gestation. We aimed to gain insight into the incidence, clinical outcomes and treatment strategies, in three academic referral centers in the Netherlands over the last nine years.

METHODS

We performed a multicenter retrospective cohort study of all patients with NEC (Bell stage ≥2a) in three academic referral centers diagnosed between 2005 and 2013. Outcome measures consisted of incidence, changes in clinical presentation, treatment strategies and mortality.

RESULTS

Between 2005 and 2013 14,161 children were admitted to the neonatal intensive care unit in the three centers. The overall percentage of children born at a gestational age of 24weeks and 25weeks increased with 1.7% after the introduction of the guidelines in 2006 and 2010. The incidence of NEC increased significantly (period 2005-2007: 2.1%; period 2008-2010 3.9%; period 2011-2013: 3.4%; P=0.001). We observed a significant decrease of peritoneal drainages (↓16%; P=0.001) and a decrease of laparotomies (↓24%; P=0.002). The mortality rate (33% in 2011-2013) remained unchanged.

CONCLUSION

The incidence of NEC significantly increased in the last nine years. The increase in incidence of NEC seemed to be related to an increase in infants born at a gestational age of 24 and 25weeks. The percentage of patients needing surgery decreased, while 30-day mortality did not change.

LEVEL OF EVIDENCE

Level IV.

The Role of Mucosal Immunity in the Pathogenesis of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is the most devastating gastrointestinal disease of prematurity. Although the precise cause is not well understood, the main risk factors thought to contribute to NEC include prematurity, formula feeding, and bacterial colonization. Recent evidence suggests that NEC develops as a consequence of intestinal hyper-responsiveness to microbial ligands upon bacterial colonization in the preterm infant, initiating a cascade of aberrant signaling events, and a robust pro-inflammatory mucosal immune response. We now have a greater understanding of important mechanisms of disease pathogenesis, such as the role of cytokines, immunoglobulins, and immune cells in NEC. In this review, we will provide an overview of the mucosal immunity of the intestine and the relationship between components of the mucosal immune system involved in the pathogenesis of NEC, while highlighting recent advances in the field that have promise as potential therapeutic targets. First, we will describe the cellular components of the intestinal epithelium and mucosal immune system and their relationship to NEC. We will then discuss the relationship between the gut microbiota and cell signaling that underpins disease pathogenesis. We will conclude our discussion by highlighting notable therapeutic advancements in NEC that target the intestinal mucosal immunity.

Current Knowledge of Necrotizing Enterocolitis in Preterm Infants and the Impact of Different Types of Enteral Nutrition Products

Preterm infants are extremely vulnerable to a range of morbidities and mortality. Underdeveloped cardiac, respiratory, gastrointestinal, and immune systems in the preterm period increase the risk of necrotizing enterocolitis (NEC), a serious disease of the gut. NEC affects 5-12% of very-low birth-weight infants, leads to surgery in 20-40% of cases, and is fatal in 25-50% of cases. There are multiple factors that may contribute to NEC, but the exact cause is not yet fully understood. Severe cases can result in intestinal resection or death, and the health care costs average >$300,000/infant when surgical management is required. Different types of nutrition may affect the onset or progression of NEC. Several studies have indicated that bovine milk-based infant formulas lead to a higher incidence of NEC in preterm infants than does human milk (HM). However, it is not clear why HM is linked to a lower incidence of NEC or why some infants fed an exclusively HM diet still develop NEC. An area that has not been thoroughly explored is the use of semielemental or elemental formulas. These specialty formulas are easy to digest and absorb in the gut and may be an effective nutritional intervention for reducing the risk of NEC. This review summarizes what is known about the factors that contribute to the onset and progression of NEC, discusses its health care cost implications, and explores the impact that different formulas and HM have on this disease.

Necrotizing enterocolitis: new insights into pathogenesis and mechanisms

Necrotizing enterocolitis (NEC) is the most frequent and lethal disease of the gastrointestinal tract of preterm infants. At present, NEC is thought to develop in the premature host in the setting of bacterial colonization, often after administration of non-breast milk feeds, and disease onset is thought to be due in part to a baseline increased reactivity of the premature intestinal mucosa to microbial ligands as compared with the full-term intestinal mucosa. The increased reactivity leads to mucosal destruction and impaired mesenteric perfusion and partly reflects an increased expression of the bacterial receptor Toll-like receptor 4 (TLR4) in the premature gut, as well as other factors that predispose the intestine to a hyper-reactive state in response to colonizing microorganisms. The increased expression of TLR4 in the premature gut reflects a surprising role for this molecule in the regulation of normal intestinal development through its effects on the Notch signalling pathway. This Review will examine the current approach to the diagnosis and treatment of NEC, provide an overview of our current knowledge regarding its molecular underpinnings and highlight advances made within the past decade towards the development of specific preventive and treatment strategies for this devastating disease.

Gene-environment interactions and the enteric nervous system: Neural plasticity and Hirschsprung disease prevention

Intestinal function is primarily controlled by an intrinsic nervous system of the bowel called the enteric nervous system (ENS). The cells of the ENS are neural crest derivatives that migrate into and through the bowel during early stages of organogenesis before differentiating into a wide variety of neurons and glia. Although genetic factors critically underlie ENS development, it is now clear that many non-genetic factors may influence the number of enteric neurons, types of enteric neurons, and ratio of neurons to glia. These non-genetic influences include dietary nutrients and medicines that may impact ENS structure and function before or after birth. This review summarizes current data about gene-environment interactions that affect ENS development and suggests that these factors may contribute to human intestinal motility disorders like Hirschsprung disease or irritable bowel syndrome.

Nitrate/Nitrite as Critical Mediators to Limit Oxidative Injury and Inflammation

SIGNIFICANCE

Nitric oxide (NO) is a critical signaling molecule marked by complex chemistry and varied biological responses depending on the context of the redox environment. In the setting of inflammation, NO can not only contribute to tissue injury and be causative of oxidative damage but can also signal as an adaptive molecule to limit inflammatory signaling in multiple cell types and tissues.

RECENT ADVANCES

An advance in our understanding of NO biology was the recognition of the nitrate-nitrite-NO axis, whereby nitrate (predominantly from dietary sources) could be converted to nitrite and nitrite could be reduced to NO.

CRITICAL ISSUES

Intriguingly, the recognition of multiple enzymes that serve as nitrite reductases in the setting of hypoxia or ischemia established the concept of nitrite as a circulating endocrine reservoir of NO, with the selective release of NO at sites that were primed for this reaction. This review highlights the anti-inflammatory roles of nitrite in numerous clinical conditions, including ischemia/reperfusion, transplant, cardiac arrest, and vascular injury, and in gastrointestinal inflammation.

FUTURE DIRECTIONS

These preclinical and clinical investigations set up further clinical trials and studies that elucidate the endogenous role this pathway plays in protection against inflammatory signaling.