Necrotizing enterocolitis

A Comparison of Sequelae After a Practice Change From Vancomycin to Ampicillin Containing Antibiotic Regimens for Necrotizing Enterocolitis

The aim of this study was to compare sequelae and acute kidney injury (AKI) occurrence among patients with necrotizing enterocolitis (NEC) after changing institutional guidelines replacing vancomycin with ampicillin for gram-positive coverage. This was a retrospective, single-center cohort analysis of patients from 2016-2020 (n = 73) with NEC at a surgical neonatal intensive care unit with a high community prevalence of methicillin-resistant Staphylococcus aureus (MRSA). Multivariate logistic regression was utilized to assess associations. Twenty-five (34%) patients had at least 1 sequela related to NEC. Ampicillin containing regimens were not associated with any sequelae type or AKI. Postmenstrual age < 29 weeks at diagnosis ([OR] 5.8 [1.2-28.8], P = .03; and receipt of vasopressors [OR] 3.3 [1.1-10.2], P = .04) were independently associated with sequalae. Stage III NEC was independently associated with AKI, OR 10.6 (2-55.6), P = .005. In conclusion, ampicillin-containing regimens are effective for NEC management at our institution despite a high prevalence of MRSA.

Recurrent Necrotizing Enterocolitis in Late Preterm and Full-Term Babies: A Case Report and Literature Review

Necrotizing enterocolitis (NEC) is a serious inflammatory condition of the intestines that primarily affects premature infants, though it can also occur in full-term infants. Diagnosing and managing recurrent NEC in full-term infants can be particularly challenging, with most requiring surgical intervention upon presentation if medical treatment is insufficient. An approach that emphasizes active medical management while minimizing excessive bowel resection tends to result in better postoperative outcomes, highlighting the need for increased awareness within the healthcare community regarding the complexities of NEC cases. The Security Forces Hospital Program in Riyadh, Saudi Arabia, conducted a study on two cases of necrotizing enterocolitis. The cases involved a full-term baby and a late preterm baby, both of whom had challenging hospital courses and required active care. The study presents a chronological order of the clinical presentation, in-hospital course, and difficulties encountered. The study also includes a brief literature review using PubMed and ProQuest databases. The first case is of a 34+6-week-old baby boy, weighing 2.26 kg at birth, who experienced a normal vaginal delivery but faced complications due to group B Streptococcus. Initially, he showed signs of hypoactivity and a distended abdomen, leading to a diagnosis of sepsis versus necrotizing enterocolitis (NEC). After medical treatment, he was discharged but later returned with worsening symptoms, prompting an ultrasound and subsequent surgery that revealed extensive NEC. Following a stoma procedure and treatment for bowel obstruction, the patient made a full recovery and had a successful stoma closure 10 weeks later. Now, almost four years old, he is thriving and doing well. In the second case, the mother gave birth to a full-term 39 + 2 weeks-old baby boy via normal spontaneous vaginal delivery, weighing 2.51 kg, with no significant antenatal issues. At 10 days old, the baby developed necrotizing enterocolitis (NEC), which was treated before discharge. However, at two months, he was readmitted with sepsis, and an abdominal X-ray showed a thickened bowel loop but no signs of NEC. An ultrasound later indicated ileocolic intussusception, leading to exploratory surgery that revealed NEC and Meckel's diverticulum, but no intussusception was found. The surgery involved creating stomas, and the baby recovered well, with plans for stoma closure 52 days later. He has since been discharged and is making progress in speech therapy after experiencing some delayed speech. Recurrent necrotizing enterocolitis is a rare condition in full-term infants, and its occurrence in de novo cases remains unclear. This condition presents significant challenges in diagnosis and management, potentially leading to long-term gastrointestinal issues or even death, highlighting the importance of prompt diagnosis and appropriate treatment. While medical management is the primary approach, surgical intervention may be required in cases where medical treatment fails, and it is crucial to avoid excessive bowel resection and ensure long-term follow-up for affected infants.

Current Practices, Challenges, and Recommendations in Enteral Nutrition After Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a neonatal disease with high mortality and morbidity. There is a lack of evidence-based recommendations on nutritional rehabilitation following NEC, and much of the current practice is guided by institutional policies and expert opinions. After a diagnosis of NEC, infants are exposed to an extended period of bowel rest and a prolonged course of antibiotics. Recognizing the patient characteristics that predict nutritional tolerance, early initiation of enteral nutrition, minimizing periods of bowel rest and antibiotic exposure, and standardization of dietary practices are the mainstay of post-NEC nutrition.

Bifidobacterium: Host-Microbiome Interaction and Mechanism of Action in Preventing Common Gut-Microbiota-Associated Complications in Preterm Infants: A Narrative Review

The development and health of infants are intertwined with the protective and regulatory functions of different microorganisms in the gut known as the gut microbiota. Preterm infants born with an imbalanced gut microbiota are at substantial risk of several diseases including inflammatory intestinal diseases, necrotizing enterocolitis, late-onset sepsis, neurodevelopmental disorders, and allergies which can potentially persist throughout adulthood. In this review, we have evaluated the role of Bifidobacterium as commonly used probiotics in the development of gut microbiota and prevention of common diseases in preterm infants which is not fully understood yet. The application of Bifidobacterium as a therapeutical approach in the re-programming of the gut microbiota in preterm infants, the mechanisms of host-microbiome interaction, and the mechanism of action of this bacterium have also been investigated, aiming to provide new insights and opportunities in microbiome-targeted interventions in personalized medicine.

Ultrasound for necrotizing enterocolitis: how can we optimize imaging and what are the most critical findings?

Necrotizing enterocolitis (NEC) is a common condition in the neonatal intensive care unit that continues to present challenges in terms of diagnosis and management. Traditionally NEC has been diagnosed and managed by clinical and radiographic findings, but US has shown promise in characterizing and prognosticating NEC. In this manuscript we review the abdominal US technique for NEC, the clinical significance of individual sonographic findings of NEC, and how US can be integrated in the clinical decision process for diagnosing and managing NEC. We also discuss the potential value-added role of a limited abdominal US protocol that focuses on the sonographic findings most indicative of a poor prognosis to include pneumoperitoneum, complex free fluid and focal fluid collections.

Development of necrotizing enterocolitis in full-term infants with duct dependent congenital heart disease

Background

Although many studies have described an increased risk of necrotizing enterocolitis in duct dependent congenital heart diseases, very few have investigated its occurrence in full-term infants with duct dependent congenital heart diseases.

Methods

To evaluate the characteristics and risk factors of necrotizing enterocolitis, we performed a retrospective review of 355 full-term infants with duct dependent congenital heart diseases who received prostaglandin E1 therapy from April 2000 to May 2020.

Results

Necrotizing enterocolitis was observed in 10 patients (3.0%). Their average gestational age and birth weight were 38.2 weeks and 2783.5 g, respectively. The median age at diagnosis was 8.0 days (2–70 days). One patient was diagnosed with necrotizing enterocolitis stage IIA, five with stage IIB, two with stage IIIA, and two with stage IIIB; two (20%) received surgical treatment. The duct dependent pulmonary circulation group had higher frequencies of necrotizing enterocolitis (4.4%) than the duct dependent systemic circulation (2.0%) and parallel circulation (1.3%) groups. The necrotizing enterocolitis and the other groups had significantly different birth weight (2783.5 g vs 3170.9 g, respectively) and gestational age (38.2 weeks vs 39.1 weeks, respectively). Gestational age under 38 weeks (OR 8.87, p = 0.002), birth weight of < 2500 g (OR 5.1, p = 0.042), need for mechanical ventilation (OR 4.6, p = 0.021), parenteral nutrition (OR 107.7, p < 0.001), and functional single ventricle (OR 5.8, p = 0.009) were significant risk factors. The case-fatality rate was higher in the necrotizing enterocolitis (40.0%) than in the other group (8.3%, p = 0.009).

Conclusions

Three percent of full-term infants with duct dependent congenital heart diseases developed necrotizing enterocolitis. Neonates with low birth weight, gestational age less than 38 weeks, functional single ventricle, or receiving assisted mechanical ventilation or parenteral nutrition are at increased risk.

Vitamin D status in very low birth weight infants and response to vitamin D intake during their NICU stays: a prospective cohort study

OBJECTIVE

To evaluate vitamin D status in very low birth weight (VLBW) infants and response to vitamin D intake.

STUDY DESIGN

In this prospective cohort study of VLBW infants, 25-hydroxyvitamin D [25(OH)D] was measured regularly starting at birth. Daily vitamin D intake was estimated from parenteral and enteral sources.

RESULTS

Of the included 83 infants born between November 2016 and March 2018, 44 (53%) had 25(OH)D < 30 ng/mL at birth but achieved vitamin D sufficiency (VDS) by 3 weeks while receiving 120-400 IU/day. Twenty-three (27.7%) infants had at least one 25(OH)D level >100 ng/mL during the study period. Infants whose intake was > 600 IU/day had higher prevalence of vitamin D excess (VDE).

CONCLUSION

In our study, low 25(OH)D was common in VLBW infants at birth. Vitamin D intake of 120-260 IU/day from parenteral and 200-400 IU/day from enteral route was appropriate for VLBW infants to achieve VDS. Doses > 600 IU/day increased risk of VDE.

Intussusception in preterm neonates: A systematic review of a rare condition

Background

While necrotizing enterocolitis (NEC) is a prevalent condition in preterm neonates admitted to neonatal intensive care unit (NICU), intussusception is exceedingly uncommon and often overlooked. This is due to the fact that they share many clinical characteristics. The initial misdiagnosis of intussusception in preterm neonates (IPN) especially has led to a delay in their management, which increases the risk of developing compromised bowel. Additionally, it is difficult to reach a diagnosis as neonatal intussusception does not have any classical radiological signs even when contrast enema is used. This systematic review is based on the published literature including case reports and case series to review the clinical features of IPN and how to differentiate it from NEC in order to shed the light on this rare disease and how having a high index of suspicion would help practitioners to make an early and accurate diagnosis

Methods

A systematic literature search to report all cases of relevant articles that reported IPN till date. All cases that were born before 37 weeks gestational age, presented within the neonatal period and having well established documentation were included in the study. Any case that did not have these criteria was excluded from our study.

Results

Only 52 cases met these criteria during the period from 1963 till date. An average of 10 days had elapsed before the cases were confirmed to have IPN either clinically or intraoperatively. The most frequent manifestations were abdominal distension and bilious gastric residuals, occurring in 85% and 77% of the cases respectively, followed by bloody stools in 43% of cases. However, this triad was present only in approximately one-third of the cases. Only 13 cases were diagnosed as having intussusception preoperatively. About two thirds of the intussusception were located in the ileum. Pathological lead point was present in 7 cases only; 4 of them were due to Meckel’s diverticulum. Nine cases only out of the 52 cases with IPN died.

Conclusion

It is crucial to detect the clues for diagnosis of intussusception because in contrast to NEC, it is unresponsive to conservative management, affects the viability of the bowel and surgery is essential.

Association of Infection in Neonates and Long-Term Neurodevelopmental Outcome

Perinatal and neonatal infection and associated inflammatory response may adversely affect brain development and lead to neurodevelopmental impairment. Factors that predict the risk of infection and subsequent adverse outcomes have been identified but substantial gaps remain in identifying mechanisms and interventions that can alter outcomes. This article describes the current epidemiology of neonatal sepsis, the pathogenesis of brain injury with sepsis, and the reported long-term neurodevelopment outcomes among survivors.

Etiology and surgical management of pediatric acute colon perforation beyond the neonatal stage

PURPOSE

Acute colon perforation is a pediatric surgical emergency. We aimed to analyze the different etiologies and clinical characteristics of acute non-traumatic colon perforation beyond the neonatal period and to identify surgical management and outcomes.

METHODS

This retrospective study included 18 patients admitted with acute colon perforation and who received surgical treatment.

RESULTS

Age of patients ranged between 1 month and 15 years. Five patients swallowed foreign objects (two swallowed magnets), two had colon perforation secondary to a malignant tumor (both colorectal adenocarcinoma) and two were iatrogenic (one prior colonoscopy, one air enema for intussusception). There was one perforation due to chemotherapy and Amyand's hernia respectively. The remaining seven patients had unknown etiologies; five of them were diagnosed with colitis. Fifteen (83.3 %) patients underwent open laparotomy, among which four attempted laparoscopy first. Three (16.7 %) patients underwent laparoscopic surgery. Fourteen (77.8 %) patients received simple suture repairs and four (22.2 %) received colonic resections and anastomosis. Four (22.2 %) patients received a protective diverting colostomy and three (16.7 %) received an ileostomy.

CONCLUSIONS

There is a wide range of etiology besides necrotizing enterocolitis and trauma, but a significant portion of children present with unknown etiology. Type of surgery elected should be dependent on the patient's etiology, disease severity and experience of surgeons.

Infection control and other stewardship strategies in late onset sepsis, necrotizing enterocolitis, and localized infection in the neonatal intensive care unit

Suspected or proven late onset sepsis, necrotizing enterocolitis, urinary tract infections, and ventilator associated pneumonia occurring after the first postnatal days contribute significantly to the total antibiotic exposures in neonatal intensive care units. The variability in definitions and diagnostic criteria in these conditions lead to unnecessary antibiotic use. The length of treatment and choice of antimicrobial agents for presumed and proven episodes also vary among centers due to a lack of supportive evidence and guidelines. Implementation of robust antibiotic stewardship programs can encourage compliance with appropriate dosages and narrow-spectrum regimens.

Optiflow vs Vapotherm as extended weaning mode from nasal continuous positive airway pressure in preterm infants ≤ 28 weeks gestational age

INTRODUCTION

Current evidence supports nasal continuous positive airway pressure (NCPAP) weaning. Heated humidified high-flow nasal cannula (HHFNC) reduces NCPAP time in infants less than 28 weeks gestational age (GA) without increasing morbidity. The aim of the study was to compare the two most frequently used HHFNC devices in weaning from NCPAP.

METHODOLOGY

We performed a retrospective matched-pair case-control study of infants less than or equal to 28 GA born in a single tertiary neonatal center managed with Optiflow or Vapotherm after being weaned from NCPAP. Patients were matched for antenatal steroid doses, delivery mode, birth plurality, GA, birthweight, gender, surfactant doses, length of mechanical ventilation, and length of NCPAP. Outcome measures were duration of HHFNC, low-flow nasal cannula, nasal bridge lesions, pneumothorax, bronchopulmonary dysplasia, postnatal steroids, necrotizing enterocolitis, sepsis, intraventricular hemorrhage, retinopathy of prematurity, length of stay, discharge weight, and mortality. Results were displayed as median (interquartile range) or ratio (percentage). Statistical analysis was performed using Mann-Whitney U and χ² tests.

RESULTS

70 patients were recruited retrospectively. Thirty-five infants were weaned from NCPAP to Optiflow and 35 infants to Vapotherm with gestational ages and birthweights of 27 GA (26-27) and 1010 g (835-1165) and 27 GA (26-28) and 960 g (788-1191), respectively. There was no statistically significant difference in any outcome measure. Infants managed with Vapotherm required a not statistically significant shorter length of time on HHFNC and low-flow nasal cannula.

CONCLUSIONS

Optiflow and Vapotherm seem to be equally effective and safe for weaning from NCPAP. However, infants weaned to Vapotherm appear to spend less time on non-invasive respiratory support.

Challenges in diagnosing necrotizing enterocolitis

One of the many challenges with necrotizing enterocolitis (NEC) remains our inability to make an accurate diagnosis of NEC. The lack of a unifying cause and multiple variations in presentations lead to great uncertainty with NEC. Separating out the needs of the researcher wanting to define NEC from the clinician and patient family's perspectives who want an accurate diagnosis for NEC is important. The need to augment and/or replace the outdated modified Bell staging criteria is crucial to improving NEC management. Emerging literature suggests that genetic susceptibility and stool microbiota signatures may help identify preterm infants at increased risk of the disease. Ongoing studies using single or multi-omic approaches may help to characterize biomarkers that will aid in the prediction or early diagnosis of NEC, as well as differentiate other causes of severe bowel injury. Bowel ultrasound shows promise in improving our diagnostic accuracy for NEC but has been slow in adoption. Patient family perspectives are key in accelerating our efforts to integrate newer diagnostic methods into practice.

Impact of Developmental Age, Necrotizing Enterocolitis Associated Stress, and Oral Therapeutic Intervention on Mucus Barrier Properties

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease of incompletely understood pathophysiology predominantly affecting premature infants. While NEC is associated with microbial invasion of intestinal tissues, and mucus modulates interactions between microbes and underlying tissues, variations in mucus barrier properties with NEC-associated risk factors have not been investigated. This study explored differences in mucus composition (total protein, DNA, mucin content, sialic acid, and immunoregulatory proteins), as well as structural and transport properties, assessed by tracking of particles and bacteria (E. coli and E. cloacae) with developmental age and exposure to NEC stressors in Sprague Dawley rats. Early developmental age (5 day old) was characterized by a more permeable mucus layer relative to 21 day old pups, suggesting immaturity may contribute to exposure of the epithelium to microbes. Exposure to NEC stressors was associated with reduced mucus permeability, which may aid in survival. Feeding with breastmilk as opposed to formula reduces incidence of NEC. Thus, NEC-stressed (N-S) rat pups were orally dosed with breastmilk components lysozyme (N-S-LYS) or docosahexaenoic acid (N-S-DHA). N-S-LYS and N-S-DHA pups had a less permeable mucus barrier relative to N-S pups, which suggests the potential of these factors to strengthen the mucus barrier and thus protect against disease.

Usefulness of peritoneal drainage in extremely low birth weight infants with intestinal perforation: a single-center experience

Purpose

Necrotizing enterocolitis and intestinal perforation are the most common surgical emergency in the neonatal intensive care unit. The purpose of this study is to evaluate if peritoneal drainage (PD) is beneficial in extremely low birth weight infants with intestinal perforation.

Methods

Retrospective cohort study of extremely low birth weight infants with a diagnosis of intestinal perforation. They were received primary PD (n = 23, PD group) or laparotomy (n = 13, LAP group). Laboratory and physiologic data were collected and organ failure scores calculated and compared between preprocedure and postprocedures. Data were analyzed using appropriated statistical tests.

Results

Between January 2005 and December 2015, 13 infants (male:female = 9:4) received laparotomy. Of 23 infants (male:female = 16:7) received PD, 20 infants received subsequent laparotomy. There were no demographic differences between PD and LAP groups. And there were no differences in total organ score in either group (PD, P = 0.486; LAP, P = 0.115). However, in LAP group, respiratory score was statistically improved between pre- and postprocedure organ failure score (P = 0.02). In physiologic parameter, PD group had a statistically worsening inotropics requirement (P = 0.025). On the other hand, LAP group had a improvement of PaO₂/FiO₂ ratio (P = 0.01).

Conclusion

PD does not improve clinical status in extremely low birth weight infants with intestinal perforation.

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.

Fetal chronic hypoxia and oxidative stress in diabetic pregnancy. Could fetal erythropoietin improve offspring outcomes?

Oxidative stress is responsible for microvascular complications (hypertension, nephropathy, retinopathy, peripheral neuropathy) of diabetes, which during pregnancy increase both maternal and fetal complications. Chronic hypoxia and hyperglycemia result in increased oxidative stress and decreased antioxidant enzyme activity. However, oxidative stress induces also anti-oxidative reactions both in pregnant diabetes patients and in their fetuses. Not all type 1 diabetes patients with long-lasting disease develop microvascular complications, which suggests that some of these patients have protective mechanisms against these complications. Fetal erythropoietin (EPO) is the main regulator of red cell production in the mother and in the fetus, but it has also protective effects in various maternal and fetal tissues. This dual effect of EPO is based on EPO receptor (EPO-R) isoforms, which differ structurally and functionally from the hematopoietic EPO-R isoform. The tissue protective effects of EPO are based on its anti-apoptotic, anti-oxidative, anti-inflammatory, cell proliferative and angiogenic properties. Recent experimental and clinical studies have shown that EPO has also positive metabolic effects on hyperglycemia and diabetes, although these have not yet been fully delineated. Whether the tissue protective and metabolic effects of EPO could have clinical benefits, are important topics for future research in diabetic pregnancies.

Robust increases in erythropoietin production by the hypoxic fetus is a response to protect the brain and other vital organs

Fetal erythropoietin (EPO), in addition to regulating erythropoiesis, has also tissue-protective properties based on its anti-inflammatory, anti-apoptotic, antioxidant, and neurotrophic effects. Notably, EPO concentrations needed for tissue protection are 100-1000 times higher than concentrations needed for regulating erythropoiesis. This dual effect of EPO is based on EPO-receptor (EPO-R) isoforms, which differ structurally and functionally. We hypothesize in this Integrated Mechanism Review that during severe fetal hypoxia the observed, but poorly understood, marked increases of fetal plasma EPO concentrations occur to protect the brain, heart, and other vital fetal organs. We further hypothesize that the concurrent marked increases of EPO in the amniotic fluid during fetal hypoxia, occur to protect newborn infants from necrotizing enterocolitis. This review presents experimental and clinical evidence in support of these hypotheses and points out unknown or poorly understood functions of EPO in the fetus. If these novel hypotheses are correct, the importance of fetal EPO as an antenatal hypoxia biomarker will become apparent. It will also likely point the way to important diagnostic and therapeutic fetal and neonatal interventions.

Role of endogenous digitalis-like factors in the clinical manifestations of severe preeclampsia: a sytematic review

Endogenous digitalis-like factor(s), originally proposed as a vasoconstrictor natriuretic hormone, was discovered in fetal and neonatal blood accidentally because it cross-reacts with antidigoxin antibodies (ADAs). Early studies using immunoassays with ADA identified the digoxin-like immuno-reactive factor(s) (EDLF) in maternal blood as well, and suggested it originated in the feto-placental unit. Mammalian digoxin-like factors have recently been identified as at least two classes of steroid compounds, plant derived ouabain (O), and several toad derived bufodienolides, most prominent being marinobufagenin (MBG). A synthetic pathway for MBG has been identified in mammalian placental tissue. Elevated maternal and fetal EDLF, O and MBG have been demonstrated in preeclampsia (PE), and inhibition of red cell membrane sodium, potassium ATPase (Na, K ATPase (NKA)) by EDLF is reversed by ADA fragments (ADA-FAB). Accordingly, maternal administration of a commercial ADA-antibody fragment (FAB) was tested in several anecdotal cases of PE, and two, small randomized, prospective, double-blind clinical trials. In the first randomized trial, ADA-FAB was administered post-partum, in the second antepartum. In the post-partum trial, ADA-FAB reduced use of antihypertensive drugs. In the second trial, there was no effect of ADA-FAB on blood pressure, but the fall in maternal creatinine clearance (CrCl) was prevented. In a secondary analysis using the pre-treatment maternal level of circulating Na, K ATPase (NKA) inhibitory activity (NKAI), ADA-FAB reduced the incidence of pulmonary edema and, unexpectedly, that of severe neonatal intraventricular hemorrhage (IVH). The fall in CrCl in patients given placebo was proportional to the circulating level of NKAI. The implications of these findings on the pathophysiology of the clinical manifestations PE are discussed, and a new model of the respective roles of placenta derived anti-angiogenic (AAG) factors (AAGFs) and EDLF is proposed.

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.

A retrospective study on the effects of exclusive donor human milk feeding in a short period after birth on morbidity and growth of preterm infants during hospitalization

The risks and benefits of feeding preterm formula (PF) versus donor human milk (DHM) in preterm infants are uncertain, and studies evaluating the efficacy of DHM to the morbidities and growth of preterm infants in the neonatal intensive care unit are confused by the need for milk fortification. We aimed to determine and compare the outcome of short-term morbidities in neonatal intensive care unit and growth between premature infants fed exclusively DHM only until a volume of 130 mL/kg/d of enteral feeding was achieved and infants fed with a PF mix after birth. The data of 132 infants with low birth weight of <1500 g and gestational age of less than 32 weeks were considered. Ninety infants were analyzed, of which 86 were discharged alive. The DHM group (n = 36) was made up of infants who were fed exclusively with DHM, whereas the PF group (n = 54) consisted of infants who were fed with a combination of PF and either DHM or human milk, until a volume of 130 mL/kg/d of enteral feeding was achieved. Once feeding in the DHM group progressed to volumes greater than 130 mL/kg/d, infants were fed fortified DHM and PF alternately. One infant (2.8%) in the DHM group had late-onset sepsis or necrotizing enterocolitis compared with 21 (38.9%) in the PF group (adjusted odds ratio 0.05, 95% confidence interval 0.01-0.41); 13 (36.1%) infants in the DHM group had bronchopulmonary dysplasia compared with 38 (70.4%) in the PF group (odds ratio 0.18, 95% confidence interval 0.05-0.41). Although the DHM group demonstrated a comparatively lower rate of weight gain, head circumference increment, and height increment from birth to the age at which an enteral feeding volume of 130 mL/kg/d was achieved, there were no significant differences in these values at 36 weeks' postmenstrual age between both groups.

Necrotizing: A historical perspective

Necrotizing enterocolitis is a devastating disease afflicting premature infants, though after 50 years of investigation, the pathophysiology remains elusive. This report describes the possible etiologic factors from a historical perspective, and outlines the importance of human milk, intestinal blood flow, and intestinal blood flow changes from a developmental perspective over the last 40-50 years.

Umbilical Venous Catheter Malposition Is Associated with Necrotizing Enterocolitis in Premature Infants

OBJECTIVE

The etiology of necrotizing enterocolitis (NEC) remains elusive despite known associations with several factors, including intestinal ischemia related to the effects of umbilical arterial catheterization on the mesenteric circulation. However, the role of the mesenteric venous circulation has yet to be studied as a potential cause of NEC. We examined the association between umbilical venous catheter (UVC) position and the development of NEC in premature infants.

DESIGN

A prospective cohort study was performed to examine the effect of UVC on portosystemic shunting via the ductus venosus (DV) and its potential role in NEC.

RESULTS

We recruited 132 premature infants, 62 of which had a birth weight ≤1,500 g. NEC was noted in 12 (19%) patients. All infants weighing ≤1,500 g underwent an attempt at UVC insertion. The UVC status was classified as appropriate (n = 39), unsuccessful (n = 9), or malpositioned (n = 14). Among the NEC patients, 7 (58%) had a UVC malposition and 3 (25%) had an unsuccessful attempt. These rates were significantly higher than in patients without NEC (14 and 12%, respectively). Multivariable logistic regression analysis confirmed birth weight (OR 2.2, 95% CI 1.2-4.7, p = 0.001) and UVC malpositioning (OR 6.9, 95% CI 1.6-35.4, p = 0.007) as independent risk factors associated with NEC.

CONCLUSIONS

Unrecognized withdrawal of a UVC into the portal vein or DV is associated with an increased incidence of NEC in infants weighing ≤1,500 g. The data support the need for additional studies to examine this effect. Confirmation of a causal relationship will raise the need to reassess UVC insertion criteria and strategies for more closely monitoring the catheter tip position.

[Risk factors for concurrent sepsis in neonates with necrotizing enterocolitis]

OBJECTIVE

To investigate the risk factors for concurrent sepsis in neonates with necrotizing enterocolitis (NEC).

METHODS

A retrospective analysis was performed for the clinical data of 273 neonates with NEC. The risk factors for concurrent sepsis were analyzed from the aspects of perinatal factors and treatment regimen before the diagnosis of NEC.

RESULTS

The incidence rate of concurrent sepsis in NEC was 32.2% (88/273). The neonates with stage III NEC had a significantly higher incidence rate of concurrent sepsis than those with stage II NEC (69.0% vs 15.9%; P<0.05). Of all neonates with sepsis, 62.5% experienced sepsis within 3 days after the diagnosis of NEC, and 37.5% experienced sepsis more than 3 days after the diagnosis. Compared with those without concurrent sepsis, the neonates with concurrent sepsis had significantly lower gestational age and birth weight (P<0.05). The neonates who had scleredema, had stage III NEC, needed gastrointestinal decompression after the diagnosis of NEC, and experienced a long time of gastrointestinal decompression tended to develop sepsis more easily (P<0.05). Scleredema (OR=9.75, 95%CI: 2.84-33.52, P<0.001), stage III NEC (OR=12.94, 95%CI : 6.82-24.55, P<0.001), and gastrointestinal decompression (OR=2.27, 95%CI: 1.14-4.5, P=0.02) were independent risk factors for concurrent sepsis in NEC.

CONCLUSIONS

Scleredema, stage III NEC, and gastrointestinal decompression are independent risk factors for concurrent sepsis in neonates with NEC.

The β-glucosidase assay: a new diagnostic tool for necrotizing enterocolitis. Sensitivity, specificity, and predictive values

We aimed to establish the utility of serum cytosolic β-glycosidase (CBG) assay as a NEC diagnosis tool. CBG activity has been compared in 192 NEC-free (NEC(-)) and 13 NEC-affected (NEC(+)) neonates, with modified Bell's stages II/III, born at Reina Sofia University Hospital; additional blood hematology, microbiology, and biochemical parameters have been assayed. NEC(+) neonates have higher serum CBG activity, 26.4 ± 12.4 mU/mg; 95 % CI (18.8-33.9), than NEC(-) infants, 11.0 ± 6.6 mU/mg; 95 % CI (10.1-11.9) (p < 0.0001). The CBG cutoff value in the ROC curve, 15.6 mU/mg, discriminates NEC(+)/NEC(-) infants with 84.6 % sensitivity, 85.9 % specificity, 37.9 positive predictive value and 98.2 negative predictive value, 6.11 positive likelihood ratio and 0.18 negative likelihood ratio, 33.61 DOR, and 0.89 AUC. A combined panel [CBG + aspartate aminotransferase + C-reactive protein] shows a 0.90 AUC value in multiple linear regressions.

CONCLUSIONS

The serum CBG level is a good NEC diagnosis test and a novel NEC biomarker which may become a screening tool.

WHAT IS KNOWN

•NEC affects ∼2.5 % of infants at NICU, ∼90 % of them weighing <1500 g. •NEC requires a careful differential diagnosis, being lethal if not diagnosed and treated. What is new: •CBG assay will be useful to determine infants without NEC and preventing unnecessary treatment. •CBG assay could discriminate NEC better than other gut-specific sera protein biomarkers.

Funisitis is more common in cervical insufficiency than in preterm labor and preterm premature rupture of membranes

OBJECTIVE

To compare the frequency of histologic chorioamnionitis and funisitis among women experiencing preterm labor, preterm premature rupture of membranes (PROM) and cervical insufficiency.

METHODS

This retrospective cohort study included singleton pregnant women who delivered at ≤36 weeks of gestation. The patients with preterm birth were subdivided into preterm labor (n=117), preterm PROM (n=153), and cervical insufficiency (n=20). All placentas were examined for pathology, according to the criteria of Salafia with minor modification. Frequencies of histologic chorioamnionitis and funisitis were evaluated according to the causes of preterm birth.

RESULTS

1) Histologic chorioamnionitis was diagnosed in 48.7% (57/117) of cases with preterm labor, 47.4% (73/153) with preterm PROM, and 75.0% (15/20) with cervical insufficiency. Funisitis was detected in 11.1% (13/117) of cases with preterm labor, 15.7% (24/153) with preterm PROM, and 40.0% (8/20) with cervical insufficiency. 2) Frequency of histologic chorioamnionitis was higher in cases with cervical insufficiency compared to preterm PROM. Frequency of funisitis was higher in cases with cervical insufficiency compared to both preterm labor and preterm PROM (P<0.05). The difference in frequency of funisitis remained significant after adjustment for gestational age at delivery and cervical dilatation at diagnosis. 3) Frequency of grade 2 funisitis was higher in cases with cervical insufficiency (35.0%, 7/20) compared to both preterm labor (6.8%, 8/117) and preterm PROM (9.8%, 15/153) (P=0.001). And the difference remained significant after adjustment for gestational age at delivery and cervical dilatation at diagnosis.

CONCLUSION

The highest frequency of funisitis was observed in cervical insufficiency among cases with spontaneous preterm birth.

The viral dsRNA analogue poly (I:C) induces necrotizing enterocolitis in neonatal mice

BACKGROUND

Necrotizing enterocolitis (NEC) is a life-threatening gastrointestinal disease in premature infants with high mortality and morbidity with uncertain pathogenesis. Recent research focused on the role of intraluminal bacteria and lipopolysaccharide (LPS). However, an additional role of viral agents in the pathogenesis of NEC has recently been postulated. We assessed the role of polyinosinic:polycytidylic acid (pIC) mimicking viral dsRNA in contributing to the development of NEC in neonatal mice.

METHODS

Four-d-old C57BL/6J pups were stressed by asphyxia and hypothermia twice daily. Animals were either fed by formula only (FO), formula containing LPS or pIC. After 72 h, mice were euthanized, intestines harvested, and the severity of NEC was assessed.

RESULTS

Breastfed mice showed no evidence of NEC. Very mild NEC-like lesions were observed in mice fed by FO. Supplementation of LPS or pIC to the formula led to increased intestinal tissue damage and inflammation compared with FO in a similar manner.

CONCLUSION

Our study demonstrates the ability of viral factors to induce NEC in neonatal mice even in the absence of LPS. Furthermore, we present a new mouse model of pIC-induced NEC which may be used to obtain further mechanistic insights in the pathogenesis of this disease.

Urinary Intestinal Fatty Acid-Binding Protein Can Distinguish Necrotizing Enterocolitis from Sepsis in Early Stage of the Disease

Necrotizing enterocolitis (NEC) is severe disease of gastrointestinal tract, yet its early symptoms are nonspecific, easily interchangeable with sepsis. Therefore, reliable biomarkers for early diagnostics are needed in clinical practice. Here, we analyzed if markers of gut mucosa damage, caspase cleaved cytokeratin 18 (ccCK18) and intestinal fatty acid-binding protein (I-FABP), could be used for differential diagnostics of NEC at early stage of disease. We collected paired serum (at enrollment and week later) and urine (collected for two days in 6 h intervals) samples from 42 patients with suspected NEC. These patients were later divided into NEC (n = 24), including 13 after gastrointestinal surgery, and sepsis (n = 18) groups using standard criteria. Healthy infants (n = 12), without any previous gut surgery, served as controls. Both biomarkers were measured by a commercial ELISA assay. There were no statistically significant differences in serum ccCK18 between NEC and sepsis but NEC patients had significantly higher levels of serum and urinary I-FABP than either sepsis patients or healthy infants. Urinary I-FABP has high sensitivity (81%) and specificity (100%) and can even distinguish NEC from sepsis in patients after surgery. Urinary I-FABP can be used to distinguish NEC from neonatal sepsis, including postoperative one, better than abdominal X-ray.

Broad-spectrum Antibiotic Plus Metronidazole May Not Prevent the Deterioration of Necrotizing Enterocolitis From Stage II to III in Full-term and Near-term Infants: A Propensity Score-matched Cohort Study

Necrotizing enterocolitis (NEC) is the most common and frequently dangerous neonatal gastrointestinal disease. Studies have shown broad-spectrum antibiotics plus anaerobic antimicrobial therapy did not prevent the deterioration of NEC among very low birth preterm infants. However, few studies about this therapy which focused on full-term and near-term infant with NEC has been reported. The aim of this study was to evaluate the effect of broad-spectrum antibiotic plus metronidazole in preventing the deterioration of NEC from stage II to III in full-term and near-term infants.A retrospective cohort study based on the propensity score (PS) 1:1 matching was performed among the full-term and near-term infants with NEC (Bell stage ≥II). All infants who received broad-spectrum antibiotics were divided into 2 groups: group with metronidazole treatment (metronidazole was used ≥4 days continuously, 15 mg/kg/day) and group without metronidazole treatment. The depraved rates of stage II NEC between the 2 groups were compared. Meanwhile, the risk factors associated with the deterioration of stage II NEC were analyzed by case-control study in the PS-matched cases.A total of 229 infants met the inclusion criteria. Before PS-matching, we found the deterioration of NEC rate in the group with metronidazole treatment was higher than that in the group without metronidazole treatment (18.1% [28/155] vs 8.1% [6/74]; P = 0.048). After PS-matching, 73 pairs were matched, and the depraved rate of NEC in the group with metronidazole treatment was not lower than that in the group without metronidazole treatment (15.1% vs 8.2%; P = 0.2). Binary logistic regression analysis showed that sepsis after NEC (odds ratio [OR] 3.748, 95% confidence interval [CI] 1.171-11.998, P = 0.03), the need to use transfusion of blood products after diagnosis of NEC (OR 8.003, 95% CI 2.365-27.087, P = 0.00), and the need of longer time for nasogastric suction were risk factors for stage II NEC progressing to stage III (OR 1.102, 95% CI 1.004-1.21, P = 0.04).Broad-spectrum antibiotic plus metronidazole may not prevent the deterioration of NEC in full-term and near-term infants. Those infants who had sepsis required transfusion of blood products, and needed longer time for nasogastric suction after stage II NEC was more likely to progress to stage III.

One-Step Multiplex PCR Assay for Differentiating Proposed New Species "Clostridium neonatale" from Closely Related Species

"Clostridium neonatale" sp. nov., previously involved in an outbreak of neonatal necrotizing enterocolitis, was recently proposed as a new species of the Clostridium genus sensu stricto. We developed a one-step multiplex colony PCR for C. neonatale identification and investigated C. neonatale intestinal colonization frequency in healthy preterm neonates.

Anaerobic antimicrobial therapy after necrotizing enterocolitis in VLBW infants

OBJECTIVE

To evaluate the effect of anaerobic antimicrobial therapy for necrotizing enterocolitis (NEC) on clinical outcomes in very low birth weight (≤1500 g) infants.

METHODS

We identified very low birth weight infants with NEC from 348 US NICUs from 1997 to 2012. Anaerobic antimicrobial therapy was defined by antibiotic exposure on the first day of NEC. We matched (1:1) infants exposed to anaerobic antimicrobial therapy with infants who were not exposed by using a propensity score stratified by NEC severity (medical and surgical). The primary composite outcome was in-hospital death or intestinal stricture. We assessed the relationship between anaerobic antimicrobial therapy and outcome by using a conditional logistic regression on the matched cohort.

RESULTS

A total of 1390 infants exposed to anaerobic antimicrobial therapy were matched with 1390 infants not exposed. Mean gestational age and birth weight were 27 weeks and 946 g, respectively, and were similar in both groups. We found no significant difference in the combined outcome of death or strictures, but strictures as a single outcome were more common in the anaerobic antimicrobial therapy group (odds ratio 1.73; 95% confidence interval, 1.11-2.72). Among infants with surgical NEC, mortality was less common with anaerobic antimicrobial therapy (odds ratio 0.71; 95% confidence interval, 0.52-0.95).

CONCLUSIONS

Anaerobic antimicrobial therapy was not associated with the composite outcome of death or strictures but was associated with an increase in intestinal strictures. This higher incidence of intestinal strictures may be explained by the fact that death is a competing outcome for intestinal strictures, and mortality was slightly lower in the anaerobic cohort. Infants with surgical NEC who received anaerobic antimicrobial therapy had lower mortality.

Enteric nervous system abnormalities are present in human necrotizing enterocolitis: potential neurotransplantation therapy

Introduction

Intestinal dysmotility following human necrotizing enterocolitis suggests that the enteric nervous system is injured during the disease. We examined human intestinal specimens to characterize the enteric nervous system injury that occurs in necrotizing enterocolitis, and then used an animal model of experimental necrotizing enterocolitis to determine whether transplantation of neural stem cells can protect the enteric nervous system from injury.

Methods

Human intestinal specimens resected from patients with necrotizing enterocolitis (n = 18), from control patients with bowel atresia (n = 8), and from necrotizing enterocolitis and control patients undergoing stoma closure several months later (n = 14 and n = 6 respectively) were subjected to histologic examination, immunohistochemistry, and real-time reverse-transcription polymerase chain reaction to examine the myenteric plexus structure and neurotransmitter expression. In addition, experimental necrotizing enterocolitis was induced in newborn rat pups and neurotransplantation was performed by administration of fluorescently labeled neural stem cells, with subsequent visualization of transplanted cells and determination of intestinal integrity and intestinal motility.

Results

There was significant enteric nervous system damage with increased enteric nervous system apoptosis, and decreased neuronal nitric oxide synthase expression in myenteric ganglia from human intestine resected for necrotizing enterocolitis compared with control intestine. Structural and functional abnormalities persisted months later at the time of stoma closure. Similar abnormalities were identified in rat pups exposed to experimental necrotizing enterocolitis. Pups receiving neural stem cell transplantation had improved enteric nervous system and intestinal integrity, differentiation of transplanted neural stem cells into functional neurons, significantly improved intestinal transit, and significantly decreased mortality compared with control pups.

Conclusions

Significant injury to the enteric nervous system occurs in both human and experimental necrotizing enterocolitis. Neural stem cell transplantation may represent a novel future therapy for patients with necrotizing enterocolitis.

16S rRNA gene sequencing, multilocus sequence analysis, and mass spectrometry identification of the proposed new species "Clostridium neonatale"

In 2002, an outbreak of necrotizing enterocolitis in a Canadian neonatal intensive care unit was associated with a proposed novel species of Clostridium, "Clostridium neonatale." To date, there are no data about the isolation, identification, or clinical significance of this species. Additionally, C. neonatale has not been formally classified as a new species, rendering its identification challenging. Indeed, the C. neonatale 16S rRNA gene sequence shows high similarity to another Clostridium species involved in neonatal necrotizing enterocolitis, Clostridium butyricum. By performing a polyphasic study combining phylogenetic analysis (16S rRNA gene sequencing and multilocus sequence analysis) and phenotypic characterization with mass spectrometry, we demonstrated that C. neonatale is a new species within the Clostridium genus sensu stricto, for which we propose the name Clostridium neonatale sp. nov. Now that the status of C. neonatale has been clarified, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) can be used for better differential identification of C. neonatale and C. butyricum clinical isolates. This is necessary to precisely define the role and clinical significance of C. neonatale, a species that may have been misidentified and underrepresented during previous neonatal necrotizing enterocolitis studies.

Antibiotics modulate intestinal immunity and prevent necrotizing enterocolitis in preterm neonatal piglets

Preterm birth, bacterial colonization, and formula feeding predispose to necrotizing enterocolitis (NEC). Antibiotics are commonly administered to prevent sepsis in preterm infants, but it is not known whether this affects intestinal immunity and NEC resistance. We hypothesized that broad-spectrum antibiotic treatment improves NEC resistance and intestinal structure, function, and immunity in neonates. Caesarean-delivered preterm pigs were fed 3 days of parenteral nutrition followed by 2 days of enteral formula. Immediately after birth, they were assigned to receive either antibiotics (oral and parenteral doses of gentamycin, ampicillin, and metronidazole, ANTI, n = 11) or saline in the control group (CON, n = 13), given twice daily. NEC lesions and intestinal structure, function, microbiology, and immunity markers were recorded. None of the ANTI but 85% of the CON pigs developed NEC lesions by day 5 (0/11 vs. 11/13, P < 0.05). ANTI pigs had higher intestinal villi (+60%), digestive enzyme activities (+53-73%), and goblet cell densities (+110%) and lower myeloperoxidase (-51%) and colonic microbial density (10(5) vs. 10(10) colony-forming units, all P < 0.05). Microarray transcriptomics showed strong downregulation of genes related to inflammation and innate immune response to microbiota and marked upregulation of genes related to amino acid metabolism, in particular threonine, glucose transport systems, and cell cycle in 5-day-old ANTI pigs. In a follow-up experiment, 5 days of antibiotics prevented NEC at least until day 10. Neonatal prophylactic antibiotics effectively reduced gut bacterial load, prevented NEC, intestinal atrophy, dysfunction, and inflammation and enhanced expression of genes related to gut metabolism and immunity in preterm pigs.

Stem cell therapy for necrotizing enterocolitis: innovative techniques and procedures for pediatric translational research

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency of newborns, especially those born prematurely. Mesenchymal stem cell (MSC) therapy has shown efficacy in protection against various forms of tissue injury, and we have demonstrated efficacy in experimental NEC. However, few studies have been performed to establish a safe and effective method of intravenous MSC infusion for newborns. Here we described a safe, non-traumatic, and effective technique for systemic MSC transplantation in newborn rats.

Heated humidified high-flow nasal cannula versus low-flow nasal cannula as weaning mode from nasal CPAP in infants ≤28 weeks of gestation

Despite the paucity of evidence, the practice of weaning nasal continuous positive airway pressure (NCPAP) is widespread. However, the most clinically effective non-invasive ventilatory support strategy remains to be determined. We compared the outcome of very premature infants with respiratory distress syndrome treated with a combination of NCPAP and heated humidified high-flow nasal cannula (HHFNC) versus NCPAP and low-flow nasal cannula (LFNC). Between 2004 and 2008, patients ≤28 weeks of gestation and <1,250 g of birth weight were treated with NCPAP + HHFNC or NCPAP + LFNC. Their respiratory and non-respiratory outcome including cost-effectiveness was compared after matching for antenatal steroid doses, mode of delivery, birth plurality, gestational age, birth weight, gender, surfactant doses, length of mechanical ventilation and clinical risk index for babies-II (CRIB-II) score. Thirty-nine infants received HHFNC + NCPAP, and 40 received NCPAP + LFNC. Median gestational age and birth weight were 27 weeks and 930 g and 27 weeks and 980 g, respectively. The total number of NCPAP days was significantly reduced by 50 % in the HHFNC group. Thirteen percent of the patients on NCPAP suffered from nasal bridge lesions compared to none on HHFNC. Respiratory and non-respiratory outcome was not significantly different otherwise. Combination of NCPAP and HHFNC reduced costs by 33 %.

CONCLUSIONS

HHFNC shortens NCPAP time without increasing overall length of non-invasive respiratory support in very preterm infants. Unlike NCPAP, HHFNC does not seem to increase the risk of nasal trauma and appears to improve cost-effectiveness whilst producing otherwise equal respiratory and non-respiratory outcomes.

Heparin-binding EGF-like growth factor (HB-EGF) therapy for intestinal injury: Application and future prospects

Throughout the past 20 years, we have been investigating the potential therapeutic roles of heparin-binding EGF-like growth factor (HB-EGF), a member of the epidermal growth factor family, in various models of intestinal injury including necrotizing enterocolitis (NEC), intestinal ischemia/reperfusion (I/R) injury, and hemorrhagic shock and resuscitation (HS/R). Our studies have demonstrated that HB-EGF acts as an effective mitogen, a restitution-inducing reagent, a cellular trophic factor, an anti-apoptotic protein and a vasodilator, via its effects on various cell types in the intestine. In the current paper, we have reviewed the application and therapeutic effects of HB-EGF in three classic animal models of intestinal injury, with particular emphasis on its protection of the intestines from NEC. Additionally, we have summarized the protective functions of HB-EGF on various target cells in the intestine. Lastly, we have provided a brief discussion focusing on the future development of HB-EGF clinical applications for the treatment of various forms of intestinal injury including NEC.

A technique for systemic mesenchymal stem cell transplantation in newborn rat pups

Mesenchymal stem cells (MSC) have the potential to aid tissue regeneration. Intravenous (IV) MSC administration is currently being assessed following tissue injury. However, few studies have been performed to establish a safe and effective method of IV MSC infusion for newborns. We have established a safe, nontraumatic and effective technique for systemic MSC transplantation in newborn rats. Yellow-fluorescent-protein (YFP)-labeled MSC were characterized using MSC markers and their differentiation potential was confirmed. Rat pups were delivered by C-section on gestational day 21. The umbilical vein (UV) was cannulated and used for IV injection of MSC or saline control, which was performed under ultrasonographic imaging. An additional control group consisted of UV MSC injection in adult mice. Mean operating time, success rate of cannulation and death rate were recorded. YFP-MSC quantification in multiple organs was performed. Mean operating time was 3.9 ± 1.1 min. The success of UV MSC injection was 92.8%. The immediate and 24 hr delayed death rate for rat pups was significantly lower than that of adult mice (p < .05). No pups receiving saline injection died. After locating the patent foramen ovale (PFO) of newborn pups by ultrasonographic imaging, extra pulse-waves and wave-shape changes were detected when MSC were injected. The number of YFP-MSC was 15.8 ± 4.1 cells per visual field (CPVF) in the lungs, 2.9 ± 1.2 CPVF in the heart, and 19.8 ± 5.0 CPVF in the intestines. We conclude that IV MSC infusion through the UV is a convenient, safe, and effective method for systemic MSC transplantation in prematurely delivered newborn rats.

Intestinal perforation in very-low-birth-weight infants with necrotizing enterocolitis

PURPOSE

To identify risk factors for intestinal perforation in very-low-birth-weight (VLBW) infants with necrotizing enterocolitis (NEC).

METHODS

Retrospective case-control study over a 10-year period, using univariate and multivariate logistic regression analyses to compare all VLBW infants treated for perforated NEC, with two age and weight-matched groups: infants with non-perforated NEC and infants without NEC.

RESULTS

Twenty infants with perforated NEC were matched to 20 infants with non-perforated NEC and 38 infants without NEC. Infants with perforated NEC were younger (p<0.01) and had higher rates of abdominal distention, metabolic acidosis, hyperglycemia and elevated liver enzymes (p<0.05). On logistic regression analysis, abdominal distention was associated with an increased risk of intestinal perforation (OR 39.8, 95% CI 2.71-585) and late onset of NEC (one-day increments) was associated with a decreased risk (OR 0.93, 95% CI 0.87-1.0).

CONCLUSION

Identification of abdominal distention at an early age in VLBW infants should lead to increased vigilance for signs of perforated NEC and may enable early intervention.

Necrotizing enterocolitis and the placenta - a key etiological link

AIM

Necrotizing enterocolitis (NEC) is the most common and severe acquired acute neonatal surgical condition, associated with premature neonates. Antenatal factors (e.g. vascular insufficiency and antenatal infections) may be important factors in "priming" the inflammatory cascade, thus predisposing to the disease. This study explores the role of placental pathology in predisposing to NEC pathogenesis.

METHODS

5338 placentas of high risk pregnancies were evaluated for placental insufficiency, infarction, and evidence of antenatal infection. Placentas of 72 premature infants developing surgical NEC (2007-2011) were identified as a separate study group and pathological placental features compared with unaffected infants.

RESULTS

Placentas of 72 of the 134 infants with surgically treated NEC (>grade 2 Bells) were available for pathologic evaluation (the remainder having been referred from other delivery units). Placentas of surgical NEC cases had significantly more evidence of noteworthy vascular pathology (placental infarcts) than high risk cases [n=38 (54.5%) versus n=1122 (21%); P<0.01]. Evidence of placental infection/chorioamnionitis or villitis plus evidence of foetal inflammatory response was present in surgical NEC infants versus unaffected infants [n=22 (31.8%) versus n=647 (12%); P<0.01], suggesting a possible pathogenic role.

CONCLUSION

This study suggests that exposure to antenatal placental infection may contribute to pathogenesis of NEC by modifying foetal vascular response and warrants further study.

Paneth cells and necrotizing enterocolitis: a novel hypothesis for disease pathogenesis

Current models of necrotizing enterocolitis (NEC) propose that intraluminal microbes destroy intestinal mucosa and activate an inflammatory cascade that ends in necrosis. We suggest an alternate hypothesis wherein NEC is caused by injury to Paneth cells (PCs) in the intestinal crypts. PCs are specialized epithelia that protect intestinal stem cells from pathogens, stimulate stem cell differentiation, shape the intestinal microbiota, and assist in repairing the gut. Our novel model of NEC uses neonatal mice and ablates PCs followed by enteral infection. We contrast this model with other animal examples of NEC and the clinical disease. Selective destruction of PCs using dithizone likely releases tumor necrosis factor-α and other inflammatory mediators. We propose that this event produces inflammation in the submucosa, generates platelet-activating factor, and induces a coagulopathy. The role of PCs in NEC is consistent with the onset of disease in preterm infants after a period of PC-related maturation, the central role of PCs in crypt-related homeostasis, the anatomic location of pneumatosis intestinalis close to the crypts, and the proximity of PCs to occluded blood vessels that cause coagulation necrosis of the intestinal villi. We offer this hypothesis to promote new thoughts about how NEC occurs and its potential prevention.

Antibiotic regimens for the empirical treatment of newborn infants with necrotising enterocolitis

BACKGROUND

Although the exact aetiology of necrotising enterocolitis (NEC) remains unknown, research suggests that it is multifactorial; suspected pathophysiological mechanisms include immaturity, intestinal ischaemia, disruption of intestinal mucosal integrity, formula feeding, hyperosmolar load to the intestine, infection and bacterial translocation. Various antibiotic regimens have been widely used in the treatment of NEC.

OBJECTIVES

To compare the efficacy of different antibiotic regimens on mortality and the need for surgery in neonates with NEC.

SEARCH METHODS

Searches were made of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2012), Oxford Database of Perinatal Trials, MEDLINE (1966 to February 2012), EMBASE (1980 to February 2012) and CINAHL (1982 to February 2012).

SELECTION CRITERIA

All randomised and quasi-randomised controlled trials where antibiotic regimens were used for treatment of NEC.

DATA COLLECTION AND ANALYSIS

Eligibility of studies for inclusion was assessed independently by each review author. The criteria and standard methods of the Cochrane Neonatal Review Group were used to assess the methodological quality of the included trials.

MAIN RESULTS

Two trials met the inclusion criteria. Faix 1988 randomised 42 premature infants with radiological diagnosis of NEC. Infants were randomised to receive either intravenous ampicillin and gentamicin or ampicillin, gentamicin and clindamycin. Hansen 1980 randomised 20 infants with NEC to receive intravenous ampicillin and gentamicin with or without enteral gentamicin.In the study by Faix 1988, there were no statistical differences in mortality (RR 1.10; 95% CI 0.32 to 3.83) or bowel perforation (RR 2.20; 95% CI 0.45 to 10.74) between the two groups although there was a trend towards higher rate of strictures in the group that received clindamycin (RR 7.20; 95% CI 0.97 to 53.36).The Hansen 1980 study showed no statistically significant difference in death, bowel perforation or development of strictures.

AUTHORS' CONCLUSIONS

There was insufficient evidence to recommend a particular antibiotic regimen for the treatment of NEC. There were concerns about adverse effects following the usage of clindamycin, related to the development of strictures. To address this issue a large randomised controlled trial needs to be performed.

Heparin-binding epidermal growth factor-like growth factor and mesenchymal stem cells act synergistically to prevent experimental necrotizing enterocolitis

BACKGROUND

We have shown that administration of heparin-binding EGF (epidermal growth factor)-like growth factor (HB-EGF) protects the intestines from experimental necrotizing enterocolitis (NEC). We have also demonstrated that systemically administered mesenchymal stem cells (MSC) can engraft into injured intestines. This study investigated the effects of HB-EGF on MSC in vitro, and whether MSC and HB-EGF can act synergistically to prevent NEC in vivo.

STUDY DESIGN

In vitro, the effect of HB-EGF on MSC proliferation, migration, and apoptosis was determined. In vivo, rat pups received MSC either intraperitoneally (IP) or intravenously (IV). Pups were assigned to 1 of 7 groups: Group 1, breast-fed; Group 2, experimental NEC; Group 3, NEC+HB-EGF; Group 4, NEC+MSC IP; Group 5, NEC+HB-EGF+MSC IP; Group 6, NEC+MSC IV; or Group 7, NEC+HB-EGF+MSC IV. Mesechymal stem cell engraftment, histologic injury, intestinal permeability, and mortality were determined.

RESULTS

Heparin-binding EGF-like growth factor promoted MSC proliferation and migration, and decreased MSC apoptosis in vitro. In vivo, MSC administered IV had increased engraftment into NEC-injured intestine compared with MSC administered IP (p < 0.05). Heparin binding EGF-like growth factor increased engraftment of IP-administered MSC (p < 0.01) and IV-administered MSC (p < 0.05). Pups in Groups 3 to 7 had a decreased incidence of NEC compared with nontreated pups (Group 2), with the lowest incidence in pups treated with HB-EGF+MSC IV (p < 0.01). Pups in Group 7 had a significantly decreased incidence of intestinal dilation and perforation, and had the lowest intestinal permeability, compared with other treatment groups (p < 0.01). Pups in all experimental groups had significantly improved survival compared with pups exposed to NEC, with the best survival in Group 7 (p < 0.05).

CONCLUSIONS

Heparin-binding EGF-like growth factor and MSC act synergistically to reduce injury and improve survival in experimental NEC.

Necrotizing enterocolitis: old problem with new hope

The incidence of necrotizing enterocolitis (NEC) and mortality rate associated with this disease are not decreasing despite more than three decades of intensive research investigation and advances in neonatal intensive care. Although the etiology of NEC is not clearly elucidated, the most accepted hypothesis at present is that enteral feeding in the presence of intestinal hypoxia-ischemia-reperfusion, and colonization with pathogens provokes an inappropriately accentuated inflammatory response by the immature intestinal epithelial cells of the preterm neonate. However, delayed colonization of commensal flora with dysbiotic flora with a predominance of pathologic microorganisms plays a fundamental role in the pathogenesis of NEC. Recent studies have further identified that NEC infants have less diverse flora compared to age-matched controls without NEC. Increased gastric residual volume may be an early sign of NEC. An absolute neutrophil count of <1.5 × 10(9)/L and platelets below 100 × 10(9)/L are associated with an increased risk for mortality and gastrointestinal morbidity. Nonspecific supportive medical management should be initiated promptly. Sudden changes in vital signs such as tachycardia or impending shock may indicate perforation. A recent meta-analysis investigating using probiotics for prevention of NEC with a total of 2176 preterm very low birth weight infants found a success rate of just 1/25. Careful monitoring of the residual volume, and of serious changes in hemograms and vital signs may help in early diagnosis and prediction of when to perform medical or early surgical intervention. In term of prevention, administration of oral probiotics containing Bifidobacterium and Lactobacillus is a simple and safe method that attempts to early establish of commensal flora balance to inhibit pathogenic flora and an inflammatory response.