Immunoregulatory protein profiles of necrotizing enterocolitis versus spontaneous intestinal perforation in preterm infants

Prophylactic indomethacin, antenatal betamethasone, and the risk of intestinal perforation in infants <28 weeks' gestation

OBJECTIVE

To determine if intestinal perforations before 14 days (either spontaneous (SIP) or necrotizing enterocolitis-induced) are increased when infants who received antenatal betamethasone shortly before birth are treated with prophylactic indomethacin (PINDO).

STUDY DESIGN

Observational study of 475 infants <28 week's gestation assigned to either a PINDO-protocol (n = 231) or expectant management protocol (n = 244) during consecutive protocol epochs.

RESULTS

Intestinal perforations before 14 days occurred in 33/475 (7%). In unadjusted and adjusted models, we found no associations between PINDO-protocol and intestinal perforations. PINDO-protocol did not increase intestinal perforations or SIP-alone even when given to infants who received betamethasone <7 or <2 days before delivery. 213/231 (92%) PINDO-protocol infants actually received indomethacin. The results were unchanged when examined just in those who received indomethacin.

CONCLUSION

In our study, early intestinal perforations and SIP-alone were not increased when PINDO was used by protocol in infants who received antenatal betamethasone shortly before birth.

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

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

Mortality and neurodevelopmental outcomes of infants with spontaneous intestinal perforation: a systematic review and meta-analysis

BACKGROUND

There is limited information about the mortality and neurodevelopmental outcomes of very preterm infants (<32 weeks) with spontaneous intestinal perforation (SIP).

OBJECTIVE

To explore the association between SIP and neurodevelopmental outcomes and mortality in very preterm infants.

DATA SOURCES

Medline, EMBASE, Cochrane Library, EMCARE and MedNar.

STUDY SELECTION

Databases were searched until September 2021. Studies comparing outcomes of 'SIP' versus 'no SIP or necrotising enterocolitis (NEC)' were included.

DATA EXTRACTION

Neurodevelopmental outcomes at ≥1 year corrected age were extracted as the main outcome measure. Data were pooled separately for adjusted and unadjusted ORs using the random-effects model. The evidence level was assessed using the GRADE (Grading of Recommendations, Assessments, Development and Evaluations) framework.

RESULTS

Eighteen cohort studies (13 606 infants) were included. Meta-analysis of unadjusted ORs showed that SIP was significantly associated with increased odds of mortality, cerebral palsy, composite outcome of death or disability, visual impairment and hearing impairment. However, pooling of adjusted ORs (aOR) found significant associations only for mortality (aOR (95% CI) 2.27 (2.07 to 2.49); I²: 0%; four studies (n=10 695)), severe disability (aOR (95% CI) 2.06 (1.38 to 3.08); I²: 0%; two studies (n=321)) and composite outcome of 'death or disability' (aOR (95% CI) 2.18 (1.55 to 3.06); I²: 0%; two studies (n=321)). The level of evidence was 'low' or 'very low'.

LIMITATIONS

Lack of information on aORs from many studies.

CONCLUSIONS

SIP in very preterm infants is associated with higher odds of mortality, severe disability, and death or disability.

How Does Human Milk Protect Against Necrotizing Enterocolitis (NEC)? Targeted Validation and Time-Course Analysis of 35 Gene Responses as NEC-Signature in Fetal Intestinal Epithelial Cells

Breastfeeding reduces the risk of necrotizing enterocolitis (NEC), one of the most common causes of morbidity and mortality in preterm infants. However, the molecular substrates by which human milk (HM) offers protection against NEC are not well known. Using fetal intestinal epithelial cells treated with known NEC aggravators, namely lipopolysaccharide (LPS) and platelet-activating factor (PAF), we mapped the time-course of changes in targeted expression analysis of 35 NEC-associated genes, so-called the NEC signature. We found, first, that HM treatment fully rescued LPS/PAF-induced fetal intestinal cell death at 12 and 24 h (n = 5). Differential gene expression and bioinformatics revealed that HM did not mitigate inflammatory and cell death signals, but instead promoted cell proliferation and stress response pathways to mitigate LPS/PAF-induced inflammatory cell death. From this, epidermal growth factor (EGF) synthesis emerged as the central player in rescue of the fetal intestinal cell death. Functional validation was supported by reversal of the cellular rescue by HM following EGF knockdown by small interfering RNA. In conclusion, this study suggests that HM might offer protection against NEC through enhancing intestinal EGF production to rescue the inflammatory cell death. Future studies are warranted to verify these HM molecular protective effects in NEC models in vivo. The findings reported herein also support future research avenues to discover new therapeutics to boost intrinsic EGF production in the injured intestinal tissues in neonates with NEC, for example, by bioactive components in human milk, natural compounds, or small molecules.

Spontaneous intestinal perforation (SIP) will soon become the most common form of surgical bowel disease in the extremely low birth weight (ELBW) infant

Recent data have revealed declines in the prevalence rates of NEC over the last decade in premature infants. In contrast, SIP has either remained steady or risen during the same epoch. These trends are consistent with our knowledge of the clinical arena. The ability to discern SIP contamination within NEC datasets has slowly improved. Additionally, quality improvement efforts are being utilized to reduce NEC through stewardship of antibiotics, acid inhibitors, central lines and blood products, as well as optimization of human milk diets. These forces are moving us to a new era, where NEC will no longer be the dominant surgical intestinal disease of the extremely preterm neonate. Indeed, in the extremely low birth weight (ELBW) population, SIP may already be the most prevalent reason for abdominal surgery. In this perspective, the reader will find supporting data and references for these assertions as well as predictions for the future.

Negative Regulation of the IL-1 System by IL-1R2 and IL-1R8: Relevance in Pathophysiology and Disease

Interleukin-1 (IL-1) is a primary cytokine of innate immunity and inflammation. IL-1 belongs to a complex family including ligands with agonist activity, receptor antagonists, and an anti-inflammatory cytokine. The receptors for these ligands, the IL-1 Receptor (IL-1R) family, include signaling receptor complexes, decoy receptors, and negative regulators. Agonists and regulatory molecules co-evolved, suggesting the evolutionary relevance of a tight control of inflammatory responses, which ensures a balance between amplification of innate immunity and uncontrolled inflammation. IL-1 family members interact with innate immunity cells promoting innate immunity, as well as with innate and adaptive lymphoid cells, contributing to their differentiation and functional polarization and plasticity. Here we will review the properties of two key regulatory receptors of the IL-1 system, IL-1R2, the first decoy receptor identified, and IL-1R8, a pleiotropic regulator of different IL-1 family members and co-receptor for IL-37, the anti-inflammatory member of the IL-1 family. Their complex impact in pathology, ranging from infections and inflammatory responses, to cancer and neurologic disorders, as well as clinical implications and potential therapeutic exploitation will be presented.

Head Growth and Neurodevelopment of Preterm Infants with Surgical Necrotizing Enterocolitis and Spontaneous Intestinal Perforation

Spontaneous intestinal perforation (SIP) and surgical necrotizing enterocolitis (NEC) are intestinal conditions requiring surgical intervention in preterm infants. We aimed to compare the head growth and neurodevelopment of preterm infants with SIP and surgical NEC. A retrospective single-center study was performed in preterm infants born at less than 32 weeks of gestation and who had undergone surgery for NEC or SIP. Data from the Bayley Scales of Infant and Toddler Development 3rd Edition (Bayley-III) at 24 months of corrected age (CA) and the Korean Ages and Stages Questionnaire (K-ASQ) or Korean Developmental Screening Test (K-DST) at 36 months were collected. Among 82 eligible infants, 60 infants had surgical NEC, and 22 infants were diagnosed with SIP. Head growth was faster until CA 4 months in preterm infants with SIP than in those with surgical NEC. At 36 months, abnormal findings in the K-ASQ or K-DST were more prevalent in the NEC group than in the SIP group in the gross motor (48.2% vs. 0%, p = 0.015), fine motor (40.7% vs. 0%, p = 0.037), cognitive (55.6% vs. 12.5%, p = 0.047), and social domains (44.4% vs. 0%, p = 0.032). More studies evaluating the neurodevelopmental outcomes of preterm infants with surgical NEC and SIP are required.

The miR-223/nuclear factor I-A axis regulates inflammation and cellular functions in intestinal tissues with necrotizing enterocolitis

We previously demonstrated that microRNA(miR)‐223 is overexpressed in intestinal tissue of infants with necrotizing enterocolitis (NEC). The objective of the current study was to identify the target gene of miR‐223 and to investigate the role of the miR‐223/nuclear factor I‐A (NFIA) axis in cellular functions that underpin the pathophysiology of NEC. The target gene of miR‐223 was identified by in silico target prediction bioinformatics, luciferase assay, and western blotting. We investigated downstream signals of miR‐223 and cellular functions by overexpressing the miRNA in Caco‐2 and FHs74 cells stimulated with lipopolysaccharide or lipoteichoic acid (LTA). NFIA was identified as a target gene of miR‐223. Overexpression of miR‐223 significantly induced MYOM1 and inhibited NFIA and RGN in Caco‐2 cells, while costimulation with LTA decreased expression of GNA11, MYLK, and PRKCZ. Expression levels of GNA11, MYLK, IL‐6, and IL‐8 were increased, and levels of NFIA and RGN were decreased in FHs74 cells. These potential downstream genes were significantly correlated with levels of miR‐223 or NFIA in primary NEC tissues. Overexpression of miR‐223 significantly increased apoptosis of Caco‐2 and FHs74 cells, while proliferation of FHs74 was inhibited. These results suggest that upon binding with NFIA, miR‐223 regulates functional effectors in pathways of apoptosis, cell proliferation, G protein signaling, inflammation, and smooth muscle contraction. The miR‐223/NFIA axis may play an important role in the pathophysiology of NEC by enhancing inflammation and tissue damage.

Diagnostic Value of Serum Urokinase-Type Plasminogen Activator Receptor in Children With Acute Appendicitis

OBJECTIVES

Acute appendicitis (AA) is the most common surgical emergency in children. The accurate and timely diagnosis of AA in children can be challenging, and delayed diagnosis rates have been reported to range from 5.9% to 27.6%. Although combining clinical history and repeated physical examination with laboratory tests and radiographic imaging modalities help reach the diagnosis, novel biomarkers can support the surgeons' decision as well. The aims of this study were to evaluate a new plasma marker, urokinase-type plasminogen activator receptor (uPAR), to improve diagnostic accuracy in AA patients, and to determine a cutoff value of uPAR, which can safely include/exclude the diagnosis of AA.

METHODS

We conducted a prospective study of children who underwent surgery for AA. Patients were categorized into the following 3 groups: group 1, controls consisted of 32 healthy volunteers; group 2, patients underwent surgery for nonperforated AA (n = 35); and group 3, patients underwent surgery for perforated AA (n = 21). Blood was sampled from group 1 at the admission and from group 2 and 3 before appendectomy. Serum uPAR, white blood cell count, absolute neutrophil count (ANC), and C-reactive protein concentrations were measured.

RESULTS

Urokinase-type plasminogen activator receptor, ANC, and white blood cell count values were significantly higher in group 2 and 3 than group 1, but there was no significant difference between group 2 and 3. C-reactive protein values were significantly higher only in group 3 than other groups. The cutoff value for uPAR is 2.2 ng/mL with sensitivity of 85.7% and specificity of 84.3% and ANC is 5900 cells/mm with sensitivity of 91.1% and specificity of 96.9% to diagnose appendicitis. The specificity was 81.3% and sensitivity was raised to 98.2% when evaluated together.

CONCLUSIONS

The incorporation of uPAR count and ANC could be a strong predictor of AA in children.

Integrated analysis of a lncRNA‑mRNA network reveals a potential mechanism underlying necrotizing enterocolitis

Previous studies have shown that long non-coding RNAs (lncRNAs) serve important roles in necrotizing enterocolitis (NEC). However, the underlying mechanisms remain largely unknown. In order to examine the potential role of lncRNAs in NEC, the present study investigated lncRNA and mRNA expression profiles in NEC lesions and adjacent intestinal tissues using Next Generation Sequencing. A total of 4,202 differentially expressed lncRNAs (fold-change >2; P<0.05) and 7,860 differentially expressed mRNAs (fold-change >2; P<0.05) were identified. Moreover, 5 dysregulated lncRNAs and 5 mRNAs were randomly selected, and further assessed by reverse transcription-quantitative PCR in vitro. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses demonstrated that the differentially expressed lncRNAs were closely associated with NEC, and were enriched in ‘inflammatory response’, ‘Toll-like receptor binding’, ‘PPAR signaling pathway’, ‘PI3K-Akt signaling pathway’, ‘transforming growth factor-β signaling pathway’ and ‘hypoxia-inducible factor 1 signaling pathway’. In addition, co-expression analysis demonstrated that these lncRNAs, including lncRNA ENST00000623580, lncRNA NONHSAT180418.1, lncRNA NONHSAT125636.2 and NONHSAT087855.2, may mediate the pathogenesis and development of NEC via lncRNA-mRNA network interactions. Therefore, the present study provided a novel insight into the role of lncRNAs in NEC.

Beneficial Effect of Mildly Pasteurized Whey Protein on Intestinal Integrity and Innate Defense in Preterm and Near-Term Piglets

Background. The human digestive tract is structurally mature at birth, yet maturation of gut functions such as digestion and mucosal barrier continues for the next 1–2 years. Human milk and infant milk formulas (IMF) seem to impact maturation of these gut functions differently, which is at least partially related to high temperature processing of IMF causing loss of bioactive proteins and formation of advanced glycation end products (AGEs). Both loss of protein bioactivity and formation of AGEs depend on heating temperature and time. The aim of this study was to investigate the impact of mildly pasteurized whey protein concentrate (MP-WPC) compared to extensively heated WPC (EH-WPC) on gut maturation in a piglet model hypersensitive to enteral nutrition. Methods. WPC was obtained by cold filtration and mildly pasteurized (73 °C, 30 s) or extensively heat treated (73 °C, 30 s + 80 °C, 6 min). Preterm (~90% gestation) and near-term piglets (~96% gestation) received enteral nutrition based on MP-WPC or EH-WPC for five days. Macroscopic and histologic lesions in the gastro-intestinal tract were evaluated and intestinal responses were further assessed by RT-qPCR, immunohistochemistry and enzyme activity analysis. Results. A diet based on MP-WPC limited epithelial intestinal damage and improved colonic integrity compared to EH-WPC. MP-WPC dampened colonic IL1-β, IL-8 and TNF-α expression and lowered T-cell influx in both preterm and near-term piglets. Anti-microbial defense as measured by neutrophil influx in the colon was only observed in near-term piglets, correlated with histological damage and was reduced by MP-WPC. Moreover, MP-WPC stimulated iALP activity in the colonic epithelium and increased differentiation into enteroendocrine cells compared to EH-WPC. Conclusions. Compared to extensively heated WPC, a formula based on mildly pasteurized WPC limits gut inflammation and stimulates gut maturation in preterm and near-term piglets and might therefore also be beneficial for preterm and (near) term infants.

Surgical necrotizing enterocolitis but not spontaneous intestinal perforation is associated with adverse neurological outcome at school age

Gastrointestinal complications during the neonatal period, i.e. necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP), are associated with adverse short-term outcome in very-low-birthweight infants (VLBWI, <1500 g birth weight). However, little is known about the neurological outcome of survivors at school age. We analysed data of 2241 infants followed-up at the age of 6 years. To determine the effect of NEC and SIP on cognitive outcome in consideration of other important confounding factors, we used multivariable logistic regression models. In addition, infants with surgical diagnosis of NEC (n = 43) or SIP (n = 41) were compared to NEC (n = 43) or SIP (n = 41) negative controls using Mahalanobis distance matching. Infants with a history for NEC had a three times increased risk (RR 3.0 [1.8-4.2], p < 0.001) to develop IQ scores <85 while history of surgical SIP did not increase the relative risk for lower IQs at school age (RR 1.0 [0.4-2.1], p = 1.000). In a matched-cohort analysis, we confirmed that infants with surgical NEC had lower mean IQ results than unaffected controls (±SD) (85±17 vs. 94±14, p = 0.023) while no differences were found for history of SIP. Our results reflect that the different aetiology and inflammatory extent of NEC and SIP may lead to disparate neurodevelopment trajectories. Hence, our data suggest a potential role of early gut-brain axis distortion in infants with NEC which needs to be further explored.

Markers of endothelial cell activation in suspected late onset neonatal sepsis in Surinamese newborns: a pilot study

BACKGROUND

Serum levels of markers of endothelial cell activation are associated with bacteremia and mortality in sepsis in adults, children, and newborns with early onset sepsis. We hypothesize that levels of these markers are associated with these outcomes in hospitalized newborns with suspected late onset neonatal sepsis (LONS).

METHODS

In this prospective cohort study, newborns admitted to the tertiary neonatal care facility of Suriname were included upon clinical suspicion of LONS and before start of antibiotic treatment, between April 1, 2015 and May 31, 2016. Serum concentrations of angiopoietin-1, angiopoietin-2, and soluble isoforms of P-selectin, E-selectin, vascular cell adhesion molecule-1 (sVCAM-1), intercellular adhesion molecule-1 (sICAM-1), platelet and endothelial cell adhesion molecule-1 (sPECAM-1), matrix metalloproteinase-9 (MMP-9), neutrophil elastase, and tissue-inhibitor of metalloproteinases-1 (TIMP-1) were measured.

RESULTS

Twenty-thee newborns were included. Baseline characteristics were similar between newborns with and without bacteremia and between non-survivors and survivors. Only soluble E-selectin (sE-selectin) was higher in newborns with bacteremia versus non-bacteremia (P=0.04) and lower in non-survivors (P=0.04). No conclusions could be made for sVCAM-1 due to high serum concentrations.

CONCLUSIONS

In conclusion, the data from this pilot study indicate that serum levels of markers of endothelial cell activation are poorly associated with bacteremia and mortality.

Interleukin-6 serum levels predict surgical intervention in infants with necrotizing enterocolitis

BACKGROUND

Symptoms at suspicion of necrotizing enterocolitis (NEC) are often nonspecific and several biomarkers have been evaluated for their discriminative power to both diagnose and predict the course from NEC suspicion to complicated disease requiring surgical intervention. Thus, we aimed to assess the utility of interleukin-6 (IL-6) to predict surgical intervention in infants suffering from NEC and, furthermore, to discriminate infants with starting NEC or late-onset sepsis (LOS).

METHODS

IL-6 serum levels at disease onset were retrospectively analyzed in 24 infants suffering from NEC as well as 16 neonates with LOS.

RESULTS

IL-6 serum levels at disease onset were significantly higher in infants suffering from NEC necessitating surgical intervention in the disease course compared to infants with medical NEC (5000 [785-5000] vs. 370 [78-4716] pg/ml, p = 0.0008) as well as gram-positive LOS (5000 [785-5000] vs. 84 [12-269] pg/ml, p = 0.0001). Infants suffering from gram-negative LOS exhibited elevated IL-6 serum levels at disease onset comparable to infants with surgical NEC (5000 [1919-5000] vs. 5000 [785-5000] pg/ml, p = 1.00).

CONCLUSION

The proinflammatory cytokine IL-6 appears to be a promising marker to distinguish surgical NEC from medical NEC at the onset of disease but cannot discriminate between surgical NEC and gram-negative LOS.

LEVEL OF EVIDENCE

II.

Antibody Microarray Analysis of Plasma Proteins for the Prediction of Histologic Chorioamnionitis in Women With Preterm Premature Rupture of Membranes

We aimed to identify maternal blood biomarkers predictive of histologic chorioamnionitis (HCA) in the plasma of women with preterm premature rupture of membranes (PPROM) and to determine whether the combination of these biomarkers with conventional clinical variables can improve the prediction of HCA. This retrospective cohort study included 82 consecutive women with PPROM (23-34 gestational weeks) who delivered within 96 hours of blood sampling. A membrane-based human antibody microarray was used to analyze the plasma proteome. The validation of 5 candidate biomarkers of interest was performed by enzyme-linked immunosorbent assay (ELISA) in the final cohort (n = 82). Serum C-reactive protein (CRP) levels were measured at sampling. Seventy-nine molecules studied exhibited intergroup differences. Validation by ELISA confirmed higher levels of plasma matrix metalloproteinase-9 (MMP-9), interleukin-6 (IL-6), S100 A8/A9, and insulin-like growth factor-binding protein 1 (IGFBP-1), but not tissue inhibitor of metalloproteinase 1 (TIMP-1), in women with HCA than in women without HCA. Using a stepwise regression analysis, a combined prediction model was developed, which included the plasma MMP-9, serum CRP levels, and gestational age (area under the curve [AUC], 0.932). The AUC for this model was significantly greater than that for any single variable included in the predictive model. Protein-antibody microarray technology can be useful in identifying plasma-based predictors for HCA. This study suggests that plasma MMP-9, IL-6, IGFBP-1, and S100 A8/A9 are important noninvasive predictors for HCA in women with PPROM and that the best predictive model, which combined these biomarkers with conventional clinical factors, can significantly improve the predictability for HCA.

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

The specific cause of what is commonly referred to as necrotizing enterocolitis (NEC) disease has been elusive largely because it is becoming clear that this entity represents more than one disease with multifactorial pathogenic mechanisms. Furthermore, finding clear and consistent diagnostic biomarkers will be difficult until the different subsets of what we are calling this disease are better delineated. In this introductory chapter, we discuss different disease entities that are frequently termed "NEC" in the newborn infant. We hope this will set the stage for more focused research and development of preventative measures for at least the most common forms of this disease.

Tuning inflammation and immunity by the negative regulators IL-1R2 and IL-1R8

Interleukin-1 receptor family members (ILRs) and Toll-Like Receptors (TLRs) are key players in immunity and inflammation and are tightly regulated at different levels. Most cell types, including cells of the innate and adaptive immune system express ILRs and TLRs. In addition, IL-1 family members are emerging as key players in the differentiation and function of innate and adaptive lymphoid cells. IL-1R2 and IL-1R8 (also known as TIR8 or SIGIRR) are members of the ILR family acting as negative regulators of the IL-1 system. IL-1R2 binds IL-1 and the accessory protein IL-1RAcP without activating signaling and can be released as a soluble form (sIL-1R2), thus modulating IL-1 availability for the signaling receptor. IL-1R8 dampens ILR- and TLR-mediated cell activation and it is a component of the receptor recognizing human IL-37. Here, we summarize our current understanding of the structure and function of IL-1R2 and IL-1R8, focusing on their role in different pathological conditions, ranging from infectious and sterile inflammation, to autoimmunity and cancer-related inflammation. We also address the emerging evidence regarding the role of IL-1R8 as a crucial checkpoint molecule in NK cells in anti-cancer and antiviral activity and the potential therapeutic implications of IL-1R8 blockade in specific pathological contexts.

Interleukin-1 Receptor 2: A New Biomarker for Sepsis Diagnosis and Gram-Negative/Gram-Positive Bacterial Differentiation

This study was undertaken to explore the value of interleukin-1 receptor 2 (IL1R2) as a novel potential biomarker for diagnosis of sepsis and discrimination of gram-negative (G)/gram-positive (G) bacterial sepsis. The study was performed in Kunming mice and septic patients. Inactive Escherichia coli or Staphylococcus aureus were used to stimulate Kunming mice (10 CFU/kg). In clinical study, septic patients with different pathogen infection were studied, and healthy volunteers and patients with systemic inflammatory response syndrome without definite infection were enrolled as control. IL1R2 transcriptions of human subjects' peripheral leukocytes were measured by real-time quantitative polymerase chain reaction assay. IL1R2 serum concentrations of mice and human subjects were measured by enzyme-linked immunosorbent assay. The value of IL1R2 as a biomarker was compared with procalcitonin (PCT), C-reactive protein (CRP), and Acute Physiology and Chronic Health Evaluation II (APACHE II). The results showed that IL1R2 expression was upregulated in mice treated with inactive Escherichia coli and septic patients. The elevation of serum IL1R2 was more significant in septic patients infected by Escherichia coli or G bacteria than in those infected by Staphylococcus aureus or G bacteria. For sepsis diagnosis and G/G bacterial sepsis discrimination, serum IL1R2 was more sensitive and specific than the traditional biomarkers such as PCT, CRP, and APACHE II as shown by the receiver operating characteristic curves. It was suggested that IL1R2 was a potential biomarker for diagnosis and G/G bacterial differentiation in sepsis.

Serial Changes of Heat Shock Protein 70 and Interleukin-8 in Burn Blister Fluid

Background

It has been reported that heat shock protein 70 (HSP70) and interleukin-8 (IL-8) play an important role in cells during the wound healing process. However, there has been no report on the effect of HSP70 and IL-8 on the blisters of burn patients.

Objective

This study aimed to evaluate the serial quantitative changes of HSP70 and IL-8 in burn blisters.

Methods

Twenty-five burn patients were included, for a total of 36 cases: twenty cases on the first day, six cases on the second, five cases on the third, three cases on the fourth, and two cases on the fifth. A correlation analysis was performed to determine the relationship between the concentration of HSP70 and IL-8 and the length of the treatment period.

Results

The HSP70 concentration was the highest on the first day, after which it decreased down to near zero. Most HSP70 was generated during the first 12 hours after the burn accident. There was no correlation between the concentration of HSP70 on the first day and the length of the treatment period. No measurable concentration of IL-8 was detected before 5 hours, but the concentration started to increase after 11 hours. The peak value was measured on the fourth day.

Conclusion

While HSP70 increased in the first few hours and decreased afterwards, IL-8 was produced after 11 hours and increased afterward in burn blister fluid. These findings provide new evidence on serial changes of inflammatory mediators in burn blister fluid.

Intestinal perforation in the premature infant

OBJECTIVE

To compare demographic data, prenatal and postnatal characteristics, laboratory data, and outcomes in a cohort of premature infants with spontaneous ileal perforation (SIP), surgical necrotizing enterocolitis (sNEC) and matched controls.

METHODS

A retrospective case-control study of infants with intestinal perforation with a birth weight (BW) less than 2,000 grams and gestational age (GA) less than 34 weeks and infants without perforation matched for BW (±150 grams) and GA (±1week).

RESULTS

130 premature infants were included, 30 infants with SIP, 35 infants with sNEC and 65 control infants. The median age of onset was 5 days postnatal age in SIP versus 25 days in sNEC (p < 0.001) and the peak onset was at 26 weeks corrected GA for SIP and 30 weeks corrected GA for sNEC. Infants with perforation had significantly higher rates of mortality (p < 0.001) and common morbidities associated with prematurity. Administration of corticosteroids and indomethacin did not differ among groups. SIP was more common among infants born to young mothers (p = 0.04) and less common in infants receiving caffeine (p = 0.02). sNEC was less common among infants receiving early red cell transfusion (p = 0.01). Perforation and sNEC trended towards less common in infants receiving inhaled nitric oxide.

CONCLUSION

SIP and sNEC are distinct clinical entities. Potential protective effects of caffeine, inhaled nitric oxide, and early transfusion should be further studied.

Cytokine decoy and scavenger receptors as key regulators of immunity and inflammation

IL-1R2 was the first decoy receptor to be described. Subsequently receptors which act as pure decoys or scavengers or trigger dampening of cytokine signaling have been described for cytokines and chemokines. Here we review the current understanding of the mode of action and significance in pathology of the chemokine atypical receptor ACKR2, the IL-1 decoy receptor IL-1R2 and the atypical IL-1 receptor family IL-1R8. Decoy and scavenger receptors with no or atypical signaling have emerged as a general strategy conserved in evolution to tune the action of cytokines, chemokines and growth factors.

The immunological landscape in necrotising enterocolitis

Necrotising enterocolitis (NEC) is an uncommon, but devastating intestinal inflammatory disease that predominantly affects preterm infants. NEC is sometimes dubbed the spectre of neonatal intensive care units, as its onset is insidiously non-specific, and once the disease manifests, the damage inflicted on the baby's intestine is already disastrous. Subsequent sepsis and multi-organ failure entail a mortality of up to 65%. Development of effective treatments for NEC has stagnated, largely because of our lack of understanding of NEC pathogenesis. It is clear, however, that NEC is driven by a profoundly dysregulated immune system. NEC is associated with local increases in pro-inflammatory mediators, e.g. Toll-like receptor (TLR) 4, nuclear factor-κB, tumour necrosis factor, platelet-activating factor (PAF), interleukin (IL)-18, interferon-gamma, IL-6, IL-8 and IL-1β. Deficiencies in counter-regulatory mechanisms, including IL-1 receptor antagonist (IL-1Ra), TLR9, PAF-acetylhydrolase, transforming growth factor beta (TGF-β)_1&2, IL-10 and regulatory T cells likely facilitate a pro-inflammatory milieu in the NEC-afflicted intestine. There is insufficient evidence to conclude a predominance of an adaptive Th1-, Th2- or Th17-response in the disease. Our understanding of the accompanying regulation of systemic immunity remains poor; however, IL-1Ra, IL-6, IL-8 and TGF-β₁ show promise as biomarkers. Here, we chart the emerging immunological landscape that underpins NEC by reviewing the involvement and potential clinical implications of innate and adaptive immune mediators and their regulation in NEC.

Differential Expression of the Activator Protein 1 Transcription Factor Regulates Interleukin-1ß Induction of Interleukin 6 in the Developing Enterocyte

The innate immune response is characterized by activation of transcription factors, nuclear factor kappa B and activator protein-1 and their downstream targets, the pro-inflammatory cytokines including interleukin 1β and interleukin 6. Normal development of this response in the intestine is critical to survival of the human neonate and delays can cause the onset of devastating inflammatory diseases such as necrotizing enterocolitis. Previous studies have addressed the role of nuclear factor kappa B in the development of the innate immune response in the enterocyte, however despite its central role in the control of multiple pro-inflammatory cytokine genes, little is known on the role of Activator Protein 1 in this response in the enterocyte. Here we show that the canonical Activator Protein 1 members, cJun and cFos and their upstream kinases JNK and p38 play an essential role in the regulation of interleukin 6 in the immature enterocyte. Our data supports a model whereby the cFos/cJun heterodimer and the more potent cJun homodimer downstream of JNK are replaced by less efficient JunD containing dimers, contributing to the decreased responsiveness to interleukin 1β and decreased interleukin 6 secretion observed in the mature enterocyte. The tissue specific expression of JunB in colonocytes and colon derived tissues together with its ability to repress Interleukin-1β induction of an Interleukin-6 gene reporter in the NCM-460 colonocyte suggests that induction of JunB containing dimers may offer an attractive therapeutic strategy for the control of IL-6 secretion during inflammatory episodes in this area of the intestine

Surgical Necrotizing Enterocolitis versus Spontaneous Intestinal Perforation in White Matter Injury on Brain Magnetic Resonance Imaging

BACKGROUND

White matter injury (WMI) is the most common form of brain injury in preterm infants. It could be induced by a systemic inflammatory response in preterm infants.

OBJECTIVES

We hypothesized that surgical necrotizing enterocolitis (surgNEC) results in more severe WMI than spontaneous intestinal perforation (SIP) on brain magnetic resonance imaging (MRI) at term-equivalent age (TEA).

METHODS

The medical records of 33 preterm infants born at less than 32 weeks of gestation who underwent surgery due to either NEC or SIP were reviewed retrospectively. White matter abnormality (WMA) on brain MRI was scored according to the diagnosis of surgNEC or SIP.

RESULTS

Nine patients were diagnosed with SIP and 24 with surgNEC. The median (range) gestational age of the SIP and surgNEC groups was 26+6 (23+3-27+6) and 25+5 weeks (23+3-31+2), respectively (p = 0.454). There were no differences in 1- and 5-min Apgar scores, mode of delivery, use of antenatal steroids, histologic chorioamnionitis, or incidence of respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD) between the two groups. Males were more prevalent in the surgNEC group (75.0 vs. 33.3%, p = 0.044), and the incidence of sepsis was higher in the surgNEC group than in the SIP group (75.0 vs. 33.3%, p = 0.044). Multivariate regression showed that the difference in WMA scores between the two groups remained significant (estimated difference = 2.418; 95% CI 0.107-4.729).

CONCLUSION

In preterm infants at less than 32 weeks of gestation, those with surgNEC showed more severe WMI than infants with SIP on brain MRI at TEA.

Are Immune Modulating Single Nucleotide Polymorphisms Associated with Necrotizing Enterocolitis?

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal emergency. The purpose of this study is to determine if functional single nucleotide polymorphisms (SNPs) in immune-modulating genes pre-dispose infants to NEC. After Institutional Review Board approval and parental consent, buccal swabs were collected for DNA extraction. TaqMan allelic discrimination assays and BglII endonuclease digestion were used to genotype specific inflammatory cytokines and TRIM21. Statistical analysis was completed using logistic regression. 184 neonates were analyzed in the study. Caucasian neonates with IL-6 (rs1800795) were over 6 times more likely to have NEC (p = 0.013; OR = 6.61, 95% CI 1.48–29.39), and over 7 times more likely to have Stage III disease (p = 0.011; OR = 7.13, (95% CI 1.56–32.52). Neonates with TGFβ-1 (rs2241712) had a decreased incidence of NEC-related perforation (p = 0.044; OR = 0.28, 95% CI: 0.08–0.97) and an increased incidence of mortality (p = 0.049; OR = 2.99, 95% CI: 1.01 – 8.86). TRIM21 (rs660) was associated with NEC-related intestinal perforation (p = 0.038; OR = 4.65, 95% CI 1.09–19.78). In premature Caucasian neonates, the functional SNP IL-6 (rs1800795) is associated with both the development and increased severity of NEC. TRIM21 (rs660) and TGFβ-1 (rs2241712) were associated with NEC- related perforation in all neonates in the cohort. These findings suggest a possible genetic role in the development of NEC.

Definitive peritoneal drainage in the extremely low birth weight infant with spontaneous intestinal perforation: predictors and hospital outcomes

OBJECTIVE

To identify characteristics associated with definitive peritoneal drainage (PD) in the extremely low birth weight infant diagnosed with spontaneous intestinal perforation (SIP). We also sought to determine whether patients requiring a second operation (salvage laparotomy) following PD are at increased risk of adverse hospital outcomes, including increased times to full enteral feedings and decreased 30-day survival.

STUDY DESIGN

We performed a retrospective chart review of infants with a birth weight <1000 g who underwent PD for SIP at a single tertiary neonatal unit from 2003 to 2012. Infants with signs of necrotizing enterocolitis on abdominal plain films, including pneumatosis intestinalis, portal venous gas or fixed, dilated small loops of bowel were excluded from the study. Perinatal and perioperative data and short-term neonatal outcomes prior to hospital discharge were collected. Comparison was made between two groups: infants treated with definitive PD vs infants requiring salvage laparotomy. Data were analyzed using independent samples t-test and Cochrane-Mantel-Haenszel.

RESULT

Eighty-nine infants who fit all inclusion criteria were identified during the study period. PD was definitive in 67 (75.3%) patients. Patients who had definitive PD vs those who required salvage laparotomy were significantly more likely to present at a later day of life (9.6±5.3 vs 5.6±2.7, P<0.0001) and to have a lower birth weight (724.6 g±132.5 vs 809.2 g±143.1, P=0.02). The administration of indomethacin or ibuprofen prior to the diagnosis of SIP was also associated with definitive PD (74.6% vs 50%, P=0.03). Comparison of feeding outcomes revealed that the time to achieve full enteral feeds was significantly longer for those who underwent a salvage laparotomy (95.9±30.2 vs 60.4±30.4 days, P<0.005). Short-term survival (>30 days) was not significantly different between the two groups.

CONCLUSION

PD was definitive therapy for the majority of neonates included in this study who were referred for surgical evaluation of SIP. Our data point to trends in being able to identify infants with SIP who are at risk for salvage laparotomy following PD, and thus, adverse nutritional outcomes. Larger, prospective studies are needed to further evaluate this specific patient population and identify those patients who are likely to succeed with PD following the diagnosis of SIP.

Inflammatory and Immune Activation in Intestinal Myofibroblasts Is Developmentally Regulated

We previously demonstrated that intestinal myofibroblasts from immature tissue produce excessive IL-8 in response to Escherichia coli lipopolysaccharide (LPS) compared to cells from mature tissue. However, it is unknown whether other cytokines and TLR agonists contribute to this developmentally regulated response. The aim of this study was to further characterize differences in inflammatory signaling in human primary intestinal fibroblasts from fetal (FIF) and infant (IIF) tissue and examine their potential to activate the adaptive immune response in vitro. Cytokine profiles of LPS-stimulated FIF and IIF were assessed by cytokine profile array. IL-8, IL-6, and IL-10 production in response to TLR2, TLR2/6, TLR4, and TLR5 agonists was determined by quantitative ELISA. The potential of activated myofibroblasts to activate adaptive immunity was determined by measuring surface class II MHC expression using flow cytometry. LPS-stimulated FIF produced a distinct proinflammatory cytokine profile consisting of MCP-1, GRO-alpha, IL-6, and IL-8 expression. FIF produced significant IL-8 and IL-6 in response to TLR4 agonist. IIF produced significant levels of IL-8 and IL-6 in the presence of TLR5 and TLR2 agonists. IFN-γ-treated FIF expressed greater HLA-DR levels compared to unstimulated controls and IFN-γ- and LPS-treated IIF. Activated FIF produce a more diverse inflammatory cytokine profile and greater levels of IL-8 and IL-6 in response to TLR4 stimulation compared to IIF. FIF express class II MHC proteins associated with activation of the adaptive immune response. These data suggest that FIF may contribute to bacterial-associated gut inflammation in the immature intestine.

Direct peritoneal resuscitation improves survival and decreases inflammation after intestinal ischemia and reperfusion injury

BACKGROUND

Direct peritoneal resuscitation (DPR) has previously been shown to alter blood flow in the small bowel mesenteric vessels in models of intestinal ischemia. However, a survival advantage or its effects on local tissue inflammation have not been previously demonstrated. We hypothesized that DPR would increase survival and decrease intestinal tissue inflammation after intestinal ischemia and reperfusion (I/R) injury.

METHODS

Eight-week-old male C57Bl6J mice were anesthetized and underwent midline laparotomy. I/R and DPR groups were exposed to superior mesenteric artery occlusion for 60 min with a nontraumatic clamp. Immediately after removal of the clamp, 1 mL of phosphate-buffered saline, 1 mL of minimal essential media, or 1 mL of minimal essential media supplemented with fetal bovine serum, penicillin and/or streptomycin, and glutamine were placed into the abdominal cavity of DPR groups. Animals were then closed in two layers and allowed to reperfuse for 6 h (cytokine analysis, n = 6 per group) or 7 d (survival analysis, n = 10 per group). After 6 h of reperfusion, animals were euthanized. Intestines were harvested and homogenized. Extracts were quantified for total protein content (Bradford assay), myeloperoxidase activity, tissue inflammatory cytokine, and growth factor production. P < 0.05 was significant.

RESULTS

I/R caused marked intestinal ischemia, significant mortality, and a significant increase in tissue cytokine and growth factor levels (P < 0.05). Seven-day survival was 30% for I/R without treatment and rose to 60% with DPR therapy using phosphate-buffered saline as the dialysate. DPR using plain MEM or MEM with supplements after ischemia increased 7-d survival to 90% (P < 0.05). DPR also significantly decreased intestinal tissue levels of myeloperoxidase, as well as intestinal tissue levels of multiple growth factors and inflammatory cytokines.

CONCLUSIONS

DPR increases survival and decreases intestinal inflammation after intestinal I/R injury. Translational applications are readily achievable and should be considered for patients with intestinal ischemic pathology.

CHRFAM7A: a human-specific α7-nicotinic acetylcholine receptor gene shows differential responsiveness of human intestinal epithelial cells to LPS

The human genome contains a unique, distinct, and human-specific α7-nicotinic acetylcholine receptor (α7nAChR) gene [CHRNA7 (gene-encoding α7-nicotinic acetylcholine receptor)] called CHRFAM7A (gene-encoding dup-α7-nicotinic acetylcholine receptor) on a locus of chromosome 15 associated with mental illness, including schizophrenia. Located 5' upstream from the "wild-type" CHRNA7 gene that is found in other vertebrates, we demonstrate CHRFAM7A expression in a broad range of epithelial cells and sequenced the CHRFAM7A transcript found in normal human fetal small intestine epithelial (FHs) cells to prove its identity. We then compared its expression to CHRNA7 in 11 gut epithelial cell lines, showed that there is a differential response to LPS when compared to CHRNA7, and characterized the CHRFAM7A promoter. We report that both CHRFAM7A and CHRNA7 gene expression are widely distributed in human epithelial cell lines but that the levels of CHRFAM7A gene expression vary up to 5000-fold between different gut epithelial cells. A 3-hour treatment of epithelial cells with 100 ng/ml LPS increased CHRFAM7A gene expression by almost 1000-fold but had little effect on CHRNA7 gene expression. Mapping the regulatory elements responsible for CHRFAM7A gene expression identifies a 1 kb sequence in the UTR of the CHRFAM7A gene that is modulated by LPS. Taken together, these data establish the presence, identity, and differential regulation of the human-specific CHRFAM7A gene in human gut epithelial cells. In light of the fact that CHRFAM7A expression is reported to modulate ligand binding to, and alter the activity of, the wild-type α7nAChR ligand-gated pentameric ion channel, the findings point to the existence of a species-specific α7nAChR response that might regulate gut epithelial function in a human-specific fashion.

Genome-wide expression profiles of necrotizing enterocolitis versus spontaneous intestinal perforation in human intestinal tissues: dysregulation of functional pathways

OBJECTIVE

To provide a comprehensive database of gene regulation and compare differentially regulated molecular networks in human tissues of necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP).

BACKGROUND

Both NEC and SIP are devastating surgical emergencies associated with high morbidity and mortality in preterm infants. Their pathophysiology and molecular mechanisms remain unclear.

METHODS

Differential whole genome microarray analysis was performed on intestinal tissues collected from NEC (n = 15) and SIP (n = 12) infants and compared with tissues collected from surgical-control patients with noninflammatory intestinal conditions (n = 14). Validation of 52 target gene expressions was performed by quantitative polymerase chain reaction. Regulatory networks of significantly affected genes were constructed according to functional pathways.

RESULTS

Extensive and significant changes of gene expression were observed in NEC tissues, which comprised multiple pathways of angiogenesis, arginine metabolism, cell adhesion and chemotaxis, extracellular matrix remodeling, hypoxia and oxidative stress, inflammation, and muscle contraction. These dysregulated genes could be networked downstream of key receptors, TLR2, TLR4, and TREM1, and mediated via NF-κB, AP-1, and HIF1A transcription factor pathways, indicating predominant microbial and inflammatory involvement. In contrast, SIP tissues exhibited much milder and less diversified expressional changes, with target genes significantly associated with G-protein-mediated muscle contraction and extracellular matrix remodeling.

CONCLUSIONS

The molecular evidence suggests that NEC and SIP are likely 2 different diseases caused by distinct etiology and pathophysiology. This first comprehensive database on differential gene expression profiles of human NEC and SIP tissues could lead to development of disease-specific diagnostic and prognostic biomarkers and new therapeutic strategies for improving outcomes.

A "multi-hit" model of neonatal white matter injury: cumulative contributions of chronic placental inflammation, acute fetal inflammation and postnatal inflammatory events

OBJECTIVE

We sought to determine whether cumulative evidence of perinatal inflammation was associated with increased risk in a "multi-hit" model of neonatal white matter injury (WMI).

METHODS

This retrospective cohort study included very preterm (gestational ages at delivery <32 weeks) live-born singleton neonates delivered at Hutzel Women's Hospital, Detroit, MI, from 2006 to 2011. Four pathologists blinded to clinical diagnoses and outcomes performed histological examinations according to standardized protocols. Neurosonography was obtained per routine clinical care. The primary indicator of WMI was ventriculomegaly (VE). Neonatal inflammation-initiating illnesses included bacteremia, surgical necrotizing enterocolitis, other infections, and those requiring mechanical ventilation.

RESULTS

A total of 425 live-born singleton neonates delivered before the 32nd week of gestation were included. Newborns delivered of pregnancies affected by chronic chorioamnionitis who had histologic evidence of an acute fetal inflammatory response were at increased risk of VE, unlike those without funisitis, relative to referent newborns without either condition, adjusting for gestational age [odds ratio (OR) 4.7; 95% confidence interval (CI) 1.4-15.8 vs. OR 1.3; 95% CI 0.7-2.6]. Similarly, newborns with funisitis who developed neonatal inflammation-initiating illness were at increased risk of VE, unlike those who did not develop such illness, compared to the referent group without either condition [OR 3.6 (95% CI 1.5-8.3) vs. OR 1.7 (95% CI 0.5-5.5)]. The greater the number of these three types of inflammation documented, the higher the risk of VE (P<0.0001).

CONCLUSION

Chronic placental inflammation, acute fetal inflammation, and neonatal inflammation-initiating illness seem to interact in contributing risk information and/or directly damaging the developing brain of newborns delivered very preterm.

Serum levels of interleukin-8 and gut-associated biomarkers in diagnosing necrotizing enterocolitis in preterm infants

BACKGROUND

In recent years several potential biochemical markers have been evaluated to facilitate a reliable diagnosis of necrotizing enterocolitis (NEC), but none have made progress to clinical routine. We performed a comparative assessment in premature infants to evaluate the diagnostic value of the routinely available cytokine interleukin (IL)-8, and two promising experimental biomarkers, the gut barrier proteins liver fatty acid binding protein (L-FABP) and intestinal fatty acid binding protein (I-FABP), respectively, for the diagnosis of NEC.

METHODS

IL-8, L-FABP, and I-FABP concentrations were analyzed in the serum of 15 infants with NEC and compared with 14 gestational age-matched infants serving as a control group.

RESULTS

Serum concentrations of I-FABP, L-FABP and IL-8 were significantly higher in infants with NEC compared with controls. IL-8 showed the highest diagnostic value with an area under the curve of 0.99, followed by L-FABP and I-FABP. In addition we found a significant correlation between IL-8 and both FABPs in infants with NEC.

CONCLUSION

Our results further advocate the possible role of IL-8 as a specific marker for NEC. The diagnostic value of IL-8 seems to be superior to I-FABP, and similar to L-FABP. The routinely availability facilitates IL-8 as a possible candidate for further clinical investigations.

Acute drop in blood monocyte count differentiates NEC from other causes of feeding intolerance

OBJECTIVE

Necrotizing enterocolitis (NEC) is characterized by macrophage infiltration into affected tissues. Because intestinal macrophages are derived from recruitment and in situ differentiation of blood monocytes in the gut mucosa, we hypothesized that increased recruitment of monocytes to the intestine during NEC reduces the blood monocyte concentration and that this fall in blood monocytes can be a useful biomarker for NEC.

STUDY DESIGN

We reviewed medical records of very-low-birth-weight (VLBW) infants treated for NEC and compared them with a matched control group comprised of infants with feeding intolerance but no signs of NEC. Clinical characteristics and absolute monocyte counts (AMCs) were recorded. Diagnostic accuracy of AMC values was tested using receiver-operator characteristics (ROC).

RESULT

We compared 69 cases and 257 controls (median 27 weeks, range 26 to 29 in both the groups). In stage II NEC, AMCs decreased from median 1.7 × 10(9) l(-1) (interquartile range (IQR) 0.98 to 2.4) to 0.8 (IQR 0.62 to 2.1); P < 0.05. In stage III NEC, monocyte counts decreased from median 2.1 × 10(9) l(-1) (IQR 0.1.5 to 3.2) to 0.8 (IQR 0.6 to 1.9); P < 0.05. There was no change in AMCs in control infants. ROC of AMC values showed a diagnostic accuracy (area under the curve) of 0.76. In a given infant with feeding intolerance, a drop in AMCs of > 20% indicated NEC with sensitivity of 0.70 (95% confidence interval (CI) 0.57 to 0.81) and specificity of 0.71 (95% CI 0.64 to 0.77).

CONCLUSION

We have identified a fall in blood monocyte concentration as a novel biomarker for NEC in VLBW infants.

Biomarkers of necrotising enterocolitis

Different categories of biomarkers of necrotising enterocolitis (NEC), including (i) non-specific mediators of the inflammatory cascade, e.g. acute phase reactants, chemokines, cytokines, and cell surface antigens, (ii) enhanced non-specific biomarkers, and (iii) specific gut-associated proteins, have distinctive biochemical characteristics and properties. The appropriateness of using these mediators in specific clinical situations, and the pros and cons of their applications as indicators or predictors of intestinal injury and NEC are highlighted. Many potentially new biomarkers such as micro-RNA, volatile organic compounds and gut microbiomes are currently under investigation. A stringent protocol for biomarker discovery is revealed so that investigators can consider this methodology as a reference for future discovery of organ-specific and/or disease-specific biomarkers for preterm infants.

Necrotizing enterocolitis: the road to zero

Necrotizing enterocolitis (NEC) continues to be the most severe gastrointestinal emergency facing the preterm neonate. The pathogenesis of NEC is still a complex and poorly understood process, but with increasing understanding of the role of enteral feeding, gut immunity and the altered gut microbiota, new opportunities to reduce overall NEC rates are now possible. Prevention strategies continue to lead as the most suitable approaches to reducing NEC, as early diagnosis and rapid effective treatment of NEC are still not optimal. Programmatic changes are equally important as subscribing to individual prevention strategies. The primary focus of this review is to summarize the best strategies we currently have to eliminate NEC within an institution.

Negative regulatory receptors of the IL-1 family

The IL-1 family of ligands and receptors has a central role in both innate and adaptive immune responses and is tightly controlled by antagonists, decoy receptors, scavengers, dominant negative molecules, miRNAs and other mechanisms, acting extracellularly or intracellularly. During evolution, the development of multiple mechanisms of negative regulation reveals the need for tight control of the biological consequences of IL-1 family ligands in order to balance local and systemic inflammation and limit immunopathology. Indeed, studies with gene targeted mice for negative regulators and genetic studies in humans provide evidence for their non-redundant role in controlling inflammation, tissue damage and adaptive responses. In addition, studies have revealed the need of negative regulation of the IL-1 family not only in disease, but also in homeostatic conditions. In this review, the negative regulation mediated by decoy receptors are presented and include IL-1R2 and IL-IL-18BP as well as atypical receptors, which include TIR8/SIGIRR, IL-1RAcPb, TIGIRR-1 and IL-1RAPL. Particular emphasis is given to IL-1R2, since its discovery is the basis for the formulation of the decoy paradigm, now considered a general strategy to counter the primary inflammatory activities of cytokines and chemokines. Emphasis is also given to TIR8, a prototypical negative regulatory receptor having non-redundant roles in limiting inflammation and adaptive responses.

Abnormal heart rate characteristics before clinical diagnosis of necrotizing enterocolitis

OBJECTIVE

Earlier diagnosis and treatment of necrotizing enterocolitis (NEC) in preterm infants, before clinical deterioration, might improve outcomes. A monitor that measures abnormal heart rate characteristics (HRC) of decreased variability and transient decelerations was developed as an early warning system for sepsis. As NEC shares pathophysiologic features with sepsis, we tested the hypothesis that abnormal HRC occur before clinical diagnosis of NEC.

STUDY DESIGN

Retrospective review of Bells stage II to III NEC cases among infants <34 weeks gestation enrolled in a prospective randomized clinical trial of HRC monitoring at three neonatal intensive care units.

RESULT

Of 97 infants with NEC and HRC data, 33 underwent surgical intervention within 1 week of diagnosis. The baseline HRC index from 1 to 3 days before diagnosis was higher in patients who developed surgical vs medical NEC (2.06±1.98 vs 1.22±1.10, P=0.009). The HRC index increased significantly 16 h before the clinical diagnosis of surgical NEC and 6 h before medical NEC. At the time of clinical diagnosis, the HRC index was higher in patients with surgical vs medical NEC (3.3±2.2 vs 1.9±1.7, P<0.001).

CONCLUSION

Abnormal HRC occur before clinical diagnosis of NEC, suggesting that continuous HRC monitoring may facilitate earlier detection and treatment.

Decoys and Regulatory "Receptors" of the IL-1/Toll-Like Receptor Superfamily

Members of the IL-1 family play a key role in innate and adaptive immunity and in the pathogenesis of diverse diseases. Members of IL-1R like receptor (ILR) family include signaling molecules and negative regulators. The latter include decoy receptors (IL-1RII; IL-18BP) and “receptors” with regulatory function (TIR8/SIGIRR; IL-1RAcPb; DIGIRR). Structural considerations suggest that also TIGIRR-1 and IL-1RAPL may have regulatory function. The presence of multiple pathways of negative regulation of members of the IL-1/IL-1R family emphasizes the need for a tight control of members of this fundamental system.

Comprehensive evaluation of 11 cytokines in premature infants with surgical necrotizing enterocolitis

OBJECTIVE

A prospective study to investigate the pattern of pro- and anti-inflammatory cytokine responses in neonates with surgical necrotizing enterocolitis (NEC) and identify those cytokines being the most promising for future research.

METHODS

A panel of 11 different cytokines were measured in 9 infants with proven NEC and compared with 18 age-matched healthy neonates.

RESULTS

The serum concentrations of the interleukins (IL)-6, IL-8, and IL-10 were significantly (32-fold to 56-fold) higher in NEC infants compared with controls. In contrast, IL-5, IFN gamma, IL-4 and IL-2 showed slightly (1.4-fold to 5.9-fold) lower levels in the NEC samples. However, these cytokines showed a very low absolute concentration in infants with NEC and in controls. The sum of the serum concentrations of IL-6, IL-8 and IL-10 was able to clearly separate infants with NEC from control samples. IL-1 beta and TNF-alpha showed no statistically different levels. The serum levels of TNF-beta and IL-12p70 were below the detection limit in more than 50% of all samples per group.

CONCLUSION

In spite of strong local inflammation only three out of eleven cytokines (IL-6, IL-8, and IL-10) showed strongly increased serum levels indicating an important role of them in the pathogenesis of NEC. At least two of these three cytokines were elevated in every single NEC patient. Thus, longitudinal monitoring of combined IL-8, IL-6, and IL-10 levels could reveal their potency in being clinical relevant markers in NEC.

Biomarkers for prediction and diagnosis of necrotizing enterocolitis

This article summarizes the commonly used biomarkers currently available for diagnosis of necrotizing enterocolitis. The most exciting advances in diagnostic tests were the use of new nucleic acid sequencing techniques (eg, next-generation sequencing) and molecular screening methods (eg, proteomics and microarray analysis) for the discovery of novel biomarkers. The new technology platform coupled with stringent protocols of biomarker discovery and validation would enable neonatologists to study biologic systems at a level never before possible and discover unique biomarkers for specific organ injury and/or disease entity.

A clinical perspective of necrotizing enterocolitis: past, present, and future

Necrotizing enterocolitis (NEC) primarily affects premature infants. It is less common in term and late preterm infants. The age of onset is inversely related to the postmenstrual age at birth. In term infants, NEC is commonly associated with congenital heart diseases. NEC has also been associated with other anomalies. More than 85% of all NEC cases occur in very low birth weight infants or in very premature infants. Despite incremental advances in our understanding of the clinical presentation and pathophysiology of NEC, universal prevention of this disease continues to elude us even in the twenty-first century.