Noninvasive measurement of fecal calprotectin and serum amyloid A combined with intestinal fatty acid-binding protein in necrotizing enterocolitis

Necrotizing enterocolitis: current understanding of the prevention and management

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

Characteristics of fecal calprotectin as an early marker for suspected necrotizing enterocolitis in newborns exclusively fed maternal breast milk: a case-control study

Objective

Numerous studies have proposed using fecal calprotectin among many biomarkers associated with necrotizing enterocolitis (NEC) diagnosis. This study aimed to evaluate fecal calprotectin as an early marker for suspected NEC (stage 1) in infants fed exclusively breast milk.

Methods

We collected 20 stool samples from newborns admitted to the neonatal intensive care unit at Aswan University Hospital diagnosed with stage I NEC. We compared them with 20 samples from matched healthy newborns. Fecal calprotectin level was measured by enzyme-linked immunosorbent assay.

Results

Fecal calprotectin level was higher in cases than in the control group (P < 0.001). Also, there was a positive correlation between fecal calprotectin and C-reactive protein in the studied cases (P = 0.001). However, there were no correlations between fecal calprotectin and sex or postnatal age.

Conclusion

Fecal calprotectin levels increase in newborns with stage I NEC. Although not specific, its sensitivity suggests a role as a potential biomarker in the evaluation of suspected NEC.

Fecal calprotectin as a non-invasive marker for the prediction of post-necrotizing enterocolitis stricture

PURPOSE

This study aimed to evaluate the clinical utility of fecal calprotectin (FC) levels during the necrotizing enterocolitis (NEC) episode to predict the onset of post-NEC intestinal stricture.

METHODS

The medical records of patients with NEC treated from April 2020 to April 2022 were recorded for this study. FC was quantified at the acute phase of NEC. FC levels were compared in patients with or without intestinal stricture. Receiver operating characteristics (ROC) analysis was constructed to determine optimal cut-offs of FC for post-NEC intestinal stricture.

RESULTS

A total of 50 infants with NEC were enrolled in this study and 14 (28%) of them eventually developed intestinal stricture. All children with intestinal stricture underwent one-stage surgery and all made it through the follow-up period alive. The median FC level was 1237.55 (741.25, 1378.80) ug/g in patients with intestinal stricture and it was significantly higher than that in the non-stricture group [158.30 (76.23, 349.13) ug/g, P < 0.001]. FC had good diagnostic accuracy for predicting intestinal stricture, according to ROC curve analysis, with an AUC area of 0.911. At an optimal cut-off value of 664.2 ug/g, sensitivity and specificity were 85.71% and 91.67%, respectively.

CONCLUSION

As a non-invasive parameter, FC has excellent efficacy and accuracy in predicting post-NEC intestinal stricture. Increased FC levels at the acute phase of NEC were associated with the development of intestinal stricture.

Emerging prediction methods for early diagnosis of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a life-threatening disease of the digestive system that occurs in the neonatal period. NEC is difficult to diagnose early and the prognosis is poor. Previous studies have reported that abnormalities can be detected before the presentation of clinical symptoms. Based on an analysis of literature related to the early prediction of NEC, we provide a detailed review on the early prediction and diagnosis methods of NEC, including ultrasound, near-infrared spectroscopy, biomarkers, and intestinal microbiota. This review aimed to provide a reference for further research and clinical practice.

Intestinal Inflammation is Significantly Associated With Length Faltering in Preterm Infants at Neonatal Intensive Care Unit Discharge

OBJECTIVE

The aim of the study was to assess intestinal inflammatory measures, urinary intestinal fatty acid-binding protein (IFABP), and fecal calprotectin (FC) by gestational age (GA) and postmenstrual age (PMA) and determine the association between intestinal inflammation and growth in preterm infants from birth to hospital discharge. We hypothesized that intestinal inflammation is associated with adverse growth in preterm infants.

METHODS

We assayed repeated measures of IFABP and FC in 72 hospitalized preterm infants (<34 weeks' gestation). We calculated weight and length z scores at birth and discharge using the Fenton growth reference. Associations between mean IFABP or FC, growth z scores at discharge, and growth faltering (weight or length z score difference <-0.8 from birth to discharge) were assessed using mixed linear and logistic regression models, adjusted for intrafamilial correlation and potential confounders: GA, sex, birth z score, race/ethnicity, and maternal age.

RESULTS

Mean IFABP was greater among infants born at earlier GA and decreased with increasing PMA. Mean FC did not vary by GA or PMA. Higher mean IFABP and FC were associated with lower discharge growth z scores and greater likelihood of growth faltering significant only for mean IFABP and discharge length z score (β = -0.353, 95% confidence interval [CI]: -0.704 to -0.002) and mean IFABP and length faltering (odds ratio [OR] 1.99, P = 0.018).

CONCLUSIONS

Intestinal inflammation, measured by IFABP, was associated with lower length z scores and length faltering at discharge. Interventions to prevent intestinal inflammation may improve linear growth among preterm infants.

Biomarkers of Necrotizing Enterocolitis: The Search Continues

Necrotizing enterocolitis (NEC) is the most common gastrointestinal (GI) emergency in the neonatal intensive care unit. Despite advances in medical care, mortality and morbidity from NEC have not changed. This is likely due to the lack of a clear understanding of this multifactorial disease, and reliable biomarkers for accurate diagnosis of NEC. Currently, the diagnosis of NEC is made by a combination of nonspecific clinical signs, symptoms, and radiological findings. Though biomarkers have been studied extensively, none offer an acceptable sensitivity or specificity to be used. This review will focus on the available literature on biomarkers for preterm NEC, acknowledging the limitations in studies including the variability of inclusion criteria, and most importantly, the lack of gold standard case definition for NEC.

Biomarkers of gut injury in neonates - where are we in predicting necrotising enterocolitis?

Despite advances in neonatal care Necrotising Enterocolitis (NEC) continues to have a significant mortality and morbidity rate, and with increasing survival of those more immature infants the population at risk of NEC is increasing. Ischaemia, reperfusion, and inflammation underpin diseases affecting intestinal blood flow causing gut injury including Necrotising Enterocolitis. There is increasing interest in tissue biomarkers of gut injury in neonates, particularly those representing changes in intestinal wall barrier and permeability, to determine whether these could be useful biomarkers of gut injury. This article reviews current and newly proposed markers of gut injury, the available literature evidence, recent advances and considers how effective they are in clinical practice. We discuss each biomarker in terms of its effectiveness in predicting NEC onset and diagnosis or predicting NEC severity and then those that will aid in surveillance and identifying those infants are greatest risk of developing NEC.

Potential Role of Serum Intestinal Fatty Acid-Binding Protein as a Marker for Early Prediction and Diagnosis of Necrotizing Enterocolitis in Preterm Neonates

Introduction:

Intestinal fatty acid-binding protein (I-FABP) is located in the apex of mature enterocytes and released into circulation; once the injury of enterocyte happens, its circulating levels are considered an early and sensitive marker of intestinal ischemia as in necrotizing enterocolitis (NEC); because of its small molecular weight, it can be detected in urine.

Aims:

The aim was to study the usefulness of both serum and urine I-FABP in early diagnosis of NEC and to correlate the serum and urinary levels.

Settings and Design:

This study was case–control design.

Methods:

Simultaneous serum and urine samples obtained at the onset of symptoms, in 40 preterms with suspected NEC, with gestational age ± 27.70 weeks and birth weight ± 1.11 kg, i.e., 20 preterms diagnosed at Stage I, 12 preterms at Stage II, and 8 preterms at Stage III, were compared with age- and weight-matched preterms with no NEC.

Statistical Analysis:

The collected data were tabulated, coded, and then analyzed using the computer program Statistical Package for the Social Science (SPSS version 22).

Results:

Serum levels of I-FABP in NEC cases were significantly higher than the control group, with a mean of 6005.77 ± 6384.77 and 1480.79 ± 1276.48 pg/ml, respectively (P < 0.001). Urine levels of I-FABP in NEC cases were significantly higher than the control group, with a mean of 5009.22 ± 3941.64 and 2677.62 ± 2257.29 pg/ml, respectively (P = 0.04). Both serum and urine I-FABP levels not only in Stage II are significantly higher than Stage I but also in Stage III are significantly higher than Stage I and II (P < 0.001, P = 0.03, respectively), which showed significant positive correlation with stages of NEC (r = 0.618; P < 0.001; r = 0.306; P = 0.049, respectively). Both serum and urine I-FABP levels had a highly significant positive correlation with each other (r = 0.406 P < 0.0001). Receiving operating characteristic curve showed an area under the curve of 0.92 and 0.81 for serum and urine I-FABP, respectively.

Conclusions:

Whether serum or urinary I-FABP is valuable in the diagnosis and prediction of NEC and strongly correlated with the disease severity and with each other.

Surgical necrotizing enterocolitis: Association between surgical indication, timing, and outcomes

BACKGROUND/PURPOSE

Despite improvements in neonatal care the outcomes of Necrotizing Enterocolitis (NEC) remain unchanged over previous decades. The study aims to explore whether different indications for surgical intervention in NEC are associated with timing of surgery and outcomes.

METHODS

Population-based, prospective, observational study of all 27 paediatric surgical centres in the United Kingdom and Ireland identified using the British Association of Paediatric Surgeons Congenital Anomalies Surveillance System from 1st February 2013 to 28th February 2014. Infants were included if they had NEC and underwent first surgical intervention within 7 days of diagnosis. Primary outcomes were death, parenteral nutrition requirement or a composite outcome of death or PN requirement at 28 days post surgery.

RESULTS

There were 133 infants meeting inclusion criteria. Indications for surgery were bowel perforation (n = 67), suspected necrotic bowel without bowel perforation and not deemed to have failed medical management (n = 20), those who had failed medical management (n = 42) and a palpable mass without any other indication (n = 4). Failed medical treatment as an indication for surgery was associated with an increased time to surgery of 30.28 (95% CI 13.46-47.10) hours from those whose indication was perforation and was also the strongest predictor of PN requirement or death at 28 days post-surgery (OR 4.54 [1.59-13.0]).

CONCLUSIONS

Failed medical treatment as an indication for surgery for NEC is associated with poor outcome. Earlier intervention in these infants represents a potential opportunity to improve outcomes in this population.

[Role of fecal calprotectin in the diagnosis of neonatal necrotizing enterocolitis: a Meta analysis]

OBJECTIVE

To study the value of fecal calprotectin (FC) in the diagnosis of neonatal necrotizing enterocolitis (NEC) through a Meta analysis.

METHODS

Web of Science, Cochrane Library, PubMed, Embase, China National Knowledge Infrastructure, Weipu Periodical Database, Wanfang Data, Chinese Biomedical Literature Database were searched for related studies published up to May 2020, with manual search as supplementation. The QUADAS criteria were used to evaluate the quality of the articles included. Meta-DiSc 1.4 and Stata 15.0 software were used to perform the Meta analysis, including the evaluation of specificity, sensitivity, likelihood ratio, and diagnostic odds ratio. The sensitivity analysis and heterogeneity testing were performed, and the summary receiver operating characteristic (SROC) curve and Fagan diagram were plotted.

RESULTS

A total of 15 articles were enrolled, involving 1 719 neonates. Among these articles, 4 had low quality, 2 had high quality, and the rest had medium quality. There was high heterogeneity between studies, and there was no threshold effect or publication bias. The random effects model analysis showed that FC had a pooled specificity of 0.80 (95%CI:0.78-0.82) and a sensitivity of 0.86 (95%CI:0.83-0.89) in the diagnosis of NEC, with a negative likelihood ratio of 0.19 (95%CI:0.14-0.26), a positive likelihood ratio of 4.71 (95%CI:3.57-6.23), and a diagnostic odds ratio of 29.56 (95%CI:17.98-48.61). The area under the SROC curve was 0.9131 and the Q^* index was 0.8456. The Fagan diagram showed that the post-test probability of NEC indicated by negative FC was 13%, while that indicated by positive FC was 86%. The Meta regression analysis showed that the heterogeneity came from other non-threshold factors.

CONCLUSIONS

FC has high potential and efficiency in the early diagnosis of NEC. FC measurement can be used for the diagnosis of NEC, but it should be combined with clinical manifestations and other related laboratory examinations.

Identification of Inflammatory Genes, Pathways, and Immune Cells in Necrotizing Enterocolitis of Preterm Infant by Bioinformatics Approaches

Background

Necrotizing enterocolitis (NEC) is one of the most serious gastrointestinal disease-causing high morbidity and mortality in premature infants. However, the underlying mechanism of the pathogenesis of NEC is still not fully understood.

Methods

RNA sequencing of intestinal specimens from 9 NEC and 5 controls was employed to quantify the gene expression levels. RNA sequencing was employed to quantify the gene expression levels. DESeq2 tool was used to identify the differentially expressed genes. The biological function, pathways, transcription factors, and immune cells dysregulated in NEC were characterized by gene set enrichment analysis.

Results

In the present study, we analyzed RNA sequencing data of NECs and controls and revealed that immune-related pathways were highly activated, while some cellular responses to external stimuli-related pathways were inactivated in NEC. Moreover, B cells, macrophages M1, and plasma cells were identified as the major cell types involved in NEC. Furthermore, we also found that inflammation-related transcription factor genes, such as STAT1, STAT2, and IRF2, were significantly activated in NEC, further suggesting that these TFs might play critical roles in NEC pathogenesis. In addition, NEC samples exhibited heterogeneity to some extent. Interestingly, two subgroups in the NEC samples were identified by hierarchical clustering analysis. Notably, B cells, T cells, Th1, and Tregs involved in adaptive immune were predicted to highly infiltrate into subgroup I, while subgroup II was significantly infiltrated by neutrophils. The heterogeneity of immune cells in NEC indicated that both innate and adaptive immunes might induce NEC-related inflammatory response.

Conclusions

In summary, we systematically analyzed inflammation-related genes, signaling pathways, and immune cells to characterize the NEC pathogenesis and samples, which greatly improved our understanding of the roles of inflammatory responses in NEC.

Diagnostic value of fecal calprotectin in necrotizing enterocolitis: A meta-analysis

BACKGROUND AND OBJECTIVES

Necrotizing enterocolitis is a common gastrointestinal disease in newborns, especially in preterm infants. Our study analyzed the value of fecal calprotectin as a biomarker in the diagnosis of NEC based on previous studies that have confirmed elevated calprotectin levels in NEC patients.

METHOD

We searched several databases including PubMed, Medline, Web of Science and Cochrane Library to identify studies of humans investigating the performance characteristics of fecal calprotectin for the diagnosis of NEC. The quality of included studies was assessed by RevMan5 software (QUADAS-2). The sensitivity, specificity and other measurements of accuracy of fecal calprotectin were pooled using Meta-DiSc software.

RESULT

A total 10 studies with 568 patients included in our meta-analysis. The pooled sensitivity, specificity, diagnostic odds ratio (DOR) and AUC were: 0.86 (95%CI: 0.80-0.91), 0.79 (95%CI: 0.75-0.83), 34.78 (95% CI: 15.30 to 79.07) and 0.92. The pooled sensitivity, specificity, DOR and AUC of subgroup analysis were: 0.85 (95%CI: 0.79-0.90), 0.89 (95%CI: 0.85-0.92), 41.03 (95% CI: 16.87 to 99.78) and 0.92 for nine studies using ELISA; 0.85 (95%CI: 0.79-0.90), 0.89 (95%CI: 0.85-0.92), 42.08 (95% CI: 18.44 to 96.04) and 0.93 for six prospective studies; 0.91 (95%CI: 0.82-0.97), 0.93 (95%CI: 0.88-0.96), 69.51 (95% CI: 17.67 to 273.40) and 0.95 for four studies of preterm infants. 0.86 (95%CI: 0.77-0.92), 0.94 (95%CI: 0.90-0.97), 53.23 (95% CI: 15.68 to 180.73) and 0.94 five studies that defined NEC as stage II or above.

CONCLUSION

Fecal calprotectin is a promising biomarker with high diagnostic value in neonatal, especially in premature infants.

Excreta biomarkers in response to different gut barrier dysfunction models and probiotic supplementation in broiler chickens

Increased intestinal permeability (IP) and inflammation are both linked with functionality of the intestinal barrier and in particular enterocytes. Currently, almost all assessment methods of the intestinal barrier function are invasive. The present study aimed to quantify selected proteins as novel biomarkers in excreta of broiler chickens to facilitate non-invasive assessment of gut barrier function using enzyme-linked immunosorbent assays (ELISA). It was further hypothesised that probiotics as feed additives may counteract gut barrier dysfunction. A 3 × 2 factorial arrangement of treatments was used with the main factors being gut barrier dysfunction models (control, rye-based diet, and dexamethasone-DEX) with and without probiotic supplementation (a three-strain Bacillus) using 72 male Ross 308 day-old chickens. Each of the 6 experimental treatments was replicated 12 times. On d 21 of age, fluorescein isothiocyanate dextran (FITC-d) uptake into serum was examined to test IP. Fresh excreta samples were collected on d 20. The biomarkers included alpha-1 antitrypsin (A1AT), intestinal fatty acid binding protein (I-FABP), lipocalin-2 (LCN2), fibronectin (FN), intestinal alkaline phosphatase (IAP), ovotransferrin (OVT) and superoxide dismutase [Cu-Zn] (SOD1). Only DEX increased (P<0.001) FITC-d passage to the blood on d 21 of age, indicating a greater IP. The excreta concentrations of A1AT, I-FABP and SOD1 were unaltered by the experimental treatments. DEX increased (P<0.05) FN concentration in excreta compared with control birds. Conversely, inclusion of rye in the diet reduced (P<0.05) FN but increased (P<0.001) OVT in excreta. Independently, DEX decreased IAP (P<0.05) in excreta compared with control and rye-fed birds. The excreta concentration of LCN2 tended (P = 0.086) to increase in birds injected by DEX. There was no demonstrable effect of probiotic addition on any of the studied parameters. Among the tested biomarkers, FN, IAP, and LCN2 revealed promise as biomarkers of intestinal barrier function quantified by ELISA kits.

The Role of Gastrointestinal-Related Fatty Acid-Binding Proteins as Biomarkers in Gastrointestinal Diseases

The fatty acid-binding proteins play a major role in intracellular transportation of long-chain fatty acids. Nine fatty acid-binding proteins have been identified, with each having individual tissue-specific functions in addition to regulation of fatty acids. This review focuses on the three fatty acid-binding proteins found in the gastrointestinal tract and discusses their role as diagnostic or disease monitoring markers in neonatal necrotizing enterocolitis, acute mesenteric ischemia, celiac disease, and inflammatory bowel disease. Of these three fatty acid-binding proteins, intestinal fatty acid-binding protein is of the most interest due to its exclusive expression in the gastrointestinal tract. The elevation of intestinal fatty acid-binding protein in blood and urine reflects enterocyte damage, regardless of the underlying cause. The short half-life of intestinal fatty acid-binding protein also means it is a relatively sensitive marker. In contrast, there is currently less evidence to support liver fatty acid-binding protein and ileal bile acid-binding protein as sensitive biomarkers in these conditions. More extensive studies with specific endpoints are required to validate the roles of these fatty acid-binding proteins in gastrointestinal diseases.

Prostaglandin E-major urinary metabolite as a noninvasive surrogate marker for infantile necrotizing enterocolitis

BACKGROUND

Early definitive diagnosis of necrotizing enterocolitis (NEC) based on Bell's staging criteria is difficult because there are few observable changes on abdominal imaging and blood chemistry tests at the onset of the disease.

PURPOSE

To investigate whether prostaglandin E-2 major urinary metabolite (PGE-MUM) can be a useful surrogate marker reflecting the disease state and severity of NEC in infants.

METHODS

Infants were enrolled in this study between January 2014 and December 2016. NEC diagnosis was based on Bell's staging criteria > Stage II or necrotic bowel observed at surgery. After diagnosis, PGE-MUM level was measured and compared with that of the other disease and healthy infant groups.

RESULTS

Median PGE-MUM value was highest in the NEC group (576 [65-3672] μg/g•Cre/BSA × 1000), followed by the other disease group (94 [57-296] μg/g•Cre/BSA × 1000) and the healthy infant group (19 [10-44] μg/g•Cre/BSA × 1000) (sensitivity: 92.3%, specificity: 81.5%, accuracy: 85.0%; p < 0.01). PGE-MUM level correlated with improved status of NEC, length of necrotic intestine, and Bell's staging criteria.

CONCLUSIONS

PGE-MUM level may be a useful surrogate biomarker reflecting the disease state of NEC. The method of urine sample collection is also advantageous, being noninvasive for infants. This is the first study reporting PGE-MUM level in NEC.

TYPE OF STUDY

Study of diagnostic test.

LEVEL OF EVIDENCE

LEVEL II.

New insights into necrotizing enterocolitis: From laboratory observation to personalized prevention and treatment

BACKGROUND/PURPOSE

Necrotizing enterocolitis (NEC) is a devastating disease of prematurity that develops after feeding, often without warning, and results in diffuse intestinal necrosis leading to sepsis and death in many cases. The lack of improvement in overall survival is influenced by nonspecific diagnostic modalities as well as inexact and nonpersonalized treatment strategies.

METHODS/RESULTS

Recently, we and others have shown that NEC develops in response to exaggerated bacterial signaling in the premature intestine, as a consequence of elevated expression and activity of the bacterial receptor toll-like receptor 4 (TLR4), which is important for normal gut development. Breast milk is a powerful TLR4 inhibitor, while mutations in TLR4 genes lead to increased NEC risk in humans, providing proof-of-concept for its role in NEC. Recently, a drug discovery approach has revealed a novel class of TLR4 inhibitors which are being developed for personalized approaches to NEC treatment.

CONCLUSION

This review will highlight the current understanding of the role of bacterial signaling in NEC pathogenesis, and will describe advances in diagnosis, prevention and treatment of NEC that may hopefully improve survival for these most fragile patients.

SYSTEMATIC REVIEW

Level of Evidence: Level II.

Necrotizing enterocolitis

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

Serial fecal calprotectin in the prediction of necrotizing enterocolitis in preterm neonates

PURPOSE

To investigate whether serial measurements of fecal calprotectin concentrations enable us to identify infants who will develop NEC prior to development of symptoms.

METHODS

Prospective matched case-control study including 100 high-risk neonates. High risk includes 1) gestational age (GA) ≤30 weeks, 2) birth-weight (BW) ≤1000 g, 3) GA 30-32 weeks and BW ≤1250 g, 4) born from a mother who received indomethacin for tocolysis. We matched every NEC subject with three controls for birth weight and gestational age. Fecal calprotectin was measured twice a week from day one until five weeks after birth or until NEC development. We analyzed differences in fecal calprotectin between NEC subjects and controls in the week preceding NEC onset and course of fecal calprotectin within subjects who developed NEC.

RESULTS

Of 100 included patients, ten (median GA 27.5 weeks [24.6-29.4], BW 1010 g [775-1630]) developed NEC. The median calprotectin concentration in all samples combined was 332 μg/g [<40-8230] μg/g feces. There were no differences between NEC subjects and controls, with a wide variation in both groups. In NEC subjects, there was no intraindividual rise in calprotectin before clinical symptoms occurred.

CONCLUSIONS

There are high concentrations and wide interindividual variations in calprotectin in preterm infants during the first weeks of life. Wide intraindividual variation further precludes the serial use of fecal calprotectin in the early detection or prediction of NEC in high risk infants.

LEVEL OF EVIDENCE

III.

Serum Markers of Necrotizing Enterocolitis: A Systematic Review

OBJECTIVE

The aim of the study was to systematically review the diagnostic utility of serum biomarkers for the diagnosis of necrotizing enterocolitis (NEC).

METHODS

We conducted an electronic and manual search of the available evidence. We included studies reporting data on the diagnostic accuracy of "serum" biomarkers for the diagnosis of NEC, available until January 2016.

RESULTS

We selected 22 studies from the 1296 articles retrieved. Only S100 A8/A9 protein and apolipoprotein-CII showed high sensitivity (100% and 96.4%, respectively) and specificity (90% and 95%, respectively) in the studies using Bell stage II NEC as target condition. High sensitivity and specificity were reported for interleukin-10 (100% and 90%), interleukin1-receptor antagonist (100% and 91.7%), intestinal fatty acid-binding protein (100% and 91%) and ischemia-modified albumin (94.7% and 92%), when tested to predict the evolution from definite to advanced NEC. Given the amount of uncertainty, the limited availability of data and heterogeneity among the populations in the different studies, we were unable to perform a meta-analysis. Major concerns about the applicability stemmed from the spectrum of patients enrolled and the inclusion of diseases different from Bell stage ≥2 NEC as target conditions.

CONCLUSIONS

We identified only few markers with good diagnostic accuracy and found an overall low quality of the studies on serum NEC biomarkers. In conclusion, data supporting their use are insufficient.

Prebiotic galacto-oligosaccharides mitigate the adverse effects of iron fortification on the gut microbiome: a randomised controlled study in Kenyan infants

OBJECTIVE

Iron-containing micronutrient powders (MNPs) reduce anaemia in African infants, but the current high iron dose (12.5 mg/day) may decrease gut Bifidobacteriaceae and Lactobacillaceae, and increase enteropathogens, diarrhoea and respiratory tract infections (RTIs). We evaluated the efficacy and safety of a new MNP formula with prebiotic galacto-oligosaccharides (GOS) combined with a low dose (5 mg/day) of highly bioavailable iron.

DESIGN

In a 4-month, controlled, double-blind trial, we randomised Kenyan infants aged 6.5-9.5 months (n=155) to receive daily (1) a MNP without iron (control); (2) the identical MNP but with 5 mg iron (2.5 mg as sodium iron ethylenediaminetetraacetate and 2.5 mg as ferrous fumarate) (Fe group); or (3) the identical MNP as the Fe group but with 7.5 g GOS (FeGOS group).

RESULTS

Anaemia decreased by ≈50% in the Fe and FeGOS groups (p<0.001). Compared with the control or FeGOS group, in the Fe group there were (1) lower abundances of Bifidobacterium and Lactobacillus and higher abundances of Clostridiales (p<0.01); (2) higher abundances of virulence and toxin genes (VTGs) of pathogens (p<0.01); (3) higher plasma intestinal fatty acid-binding protein (a biomarker of enterocyte damage) (p<0.05); and (4) a higher incidence of treated RTIs (p<0.05). In contrast, there were no significant differences in these variables comparing the control and FeGOS groups, with the exception that the abundance of VTGs of all pathogens was significantly lower in the FeGOS group compared with the control and Fe groups (p<0.01).

CONCLUSION

A MNP containing a low dose of highly bioavailable iron reduces anaemia, and the addition of GOS mitigates most of the adverse effects of iron on the gut microbiome and morbidity in African infants.

TRIAL REGISTRATION NUMBER

NCT02118402.

Biomarkers of necrotizing enterocolitis: a review of literature

Necrotizing enterocolitis (NEC) is among the most serious gastrointestinal emergency in very low birth weight (VLBW), extremely low birth weight (ELBW) and extremely low gestational age neonates (ELGAN), affecting 7-14% of these neonates. Despite extensive research, the underlying aetiology of NEC still remains blurred. Due to high mortality, morbidity and its delayed presentation, early detection of NEC is considered to be lifesaving. A number of biomarkers have been studied for early detection and prediction of severity of NEC but till date, no ideal marker has been discovered. Molecular techniques like proteomic and metabolomic have recently emerged in the field for the development of biomarkers for early detection and understanding the pathophysiology of NEC. We did literature search for identifying all biomarkers that have been used for the detection of NEC and, in this review article, we discuss these biomarkers along with the available current evidence.

Mechanisms Affecting the Gut of Preterm Infants in Enteral Feeding Trials

Large randomized controlled trials (RCTs) in preterm infants offer unique opportunities for mechanistic evaluation of the risk factors leading to serious diseases, as well as the actions of interventions designed to prevent them. Necrotizing enterocolitis (NEC) a serious inflammatory gut condition and late-onset sepsis (LOS) are common feeding and nutrition-related problems that may cause death or serious long-term morbidity and are key outcomes in two current UK National Institutes for Health Research (NIHR) trials. Speed of increasing milk feeds trial (SIFT) randomized preterm infants to different rates of increases in milk feeds with a primary outcome of survival without disability at 2 years corrected age. Enteral lactoferrin in neonates (ELFIN) randomizes infants to supplemental enteral lactoferrin or placebo with a primary outcome of LOS. This is a protocol for the mechanisms affecting the gut of preterm infants in enteral feeding trials (MAGPIE) study and is funded by the UK NIHR Efficacy and Mechanistic Evaluation programme. MAGPIE will recruit ~480 preterm infants who were enrolled in SIFT or ELFIN. Participation in MAGPIE does not change the main trial protocols and uses non-invasive sampling of stool and urine, along with any residual resected gut tissue if infants required surgery. Trial interventions may involve effects on gut microbes, metabolites (e.g., short-chain fatty acids), and aspects of host immune function. Current hypotheses suggest that NEC and/or LOS are due to a dysregulated immune system in the context of gut dysbiosis, but mechanisms have not been systematically studied within large RCTs. Microbiomic analysis will use next-generation sequencing, and metabolites will be assessed by mass spectrometry to detect volatile organic and other compounds produced by microbes or the host. We will explore differences between disease cases and controls, as well as exploring the actions of trial interventions. Impacts of this research are multiple: translation of knowledge of mechanisms promoting gut health may explain outcomes or suggest alternate strategies to improve health. Results may identify new non-invasive diagnostic or monitoring techniques, preventative or treatment strategies for NEC or LOS, or provide data useful for risk stratification in future studies. Mechanistic evaluation might be especially informative where there are not clear effects on the primary outcome (ISRCTN 12554594).

Necrotizing enterocolitis symposium: Epidemiology and early diagnosis

Despite decades of research on necrotizing enterocolitis (NEC), the outlook for infants afflicted by this devastating disease is all too often bleak. The aim of this symposium at the BAPS conference in Amsterdam was to highlight recent advances in the knowledge of the epidemiology and diagnosis of NEC. There were important contributions on the disease in the United Kingdom, both from a neonatal and from a surgical point of view, whereas colleagues from the Netherlands and elsewhere in Europe shared their insights into novel diagnostic tools, both biofluid and imaging based.

LEVEL OF EVIDENCE

Level V.

[Value of combined measurement of intestinal fatty acid-binding protein and fecal calprotectin in diagnosis of necrotizing enterocolitis in full-term neonates]

OBJECTIVE

To study the value of combined measurement of intestinal fatty acid-binding protein (I-FABP) and fecal calprotectin (FC) in the diagnosis of necrotizing enterocolitis (NEC) in full-term neonates.

METHODS

A total of 36 full-term neonates with NEC (case group) and 39 neonates without digestive system diseases (control group) were enrolled as study subjects. ELISA was used to measure the serum I-FABP level and fecal FC level, and the clinical value of I-FABP combined with FC in the diagnosis of NEC was evaluated.

RESULTS

The case group had significantly higher I-FABP and FC levels than the control group (P<0.05). In the case group, serum I-FABP level was positively correlated with fecal FC level (r=0.71, P<0.05). In the diagnosis of NEC, I-FABP alone, FC alone, and I-FABP/FC combination had sensitivities of 83.3%, 81.5%, and 79.5%, specificities of 72.5%, 75.8%, and 86.3%, and areas under the ROC curve (AUCs) of 0.82, 0.81, and 0.88. The combined measurement showed significantly higher specificity and AUC than single measurement (P<0.05).

CONCLUSIONS

Children with NEC have significant increases in I-FABP and FC levels, and there is a correlation between them. Combined measurement of I-FABP and FC can increase the specificity of the diagnosis of NEC.

Diagnostic Value of Intestinal Fatty-Acid-Binding Protein in Necrotizing Enterocolitis: A Systematic Review and Meta-Analysis

The present study was undertaken to evaluate the performance of intestinal fatty-acid-binding protein (i-FABP) in the diagnosis of newborn necrotizing enterocolitis (NEC) and prediction of surgical NEC. A comprehensive literature search was performed in PubMed and EMBASE to identify potential relevant studies. QUADAS-2 tool was used to assess the quality of the included studies. The sensitivity, specificity and other measurements of accuracy of i-FABP were pooled. Summary receiver operating characteristic curves (SROC) and area under the curve (AUC) were used to summarize overall diagnostic performance. After screening 150 titles and abstracts, followed by 32 full-text publications, 14 studies were included. The sample size, sensitivity, specificity, diagnostic odds ratio (DOR) and AUC were: plasma i-FABP 217, 0.64(95% CI 0.53 to 0.74), 0.91(95% CI 0.84 to 0.95), 14.22 (95%CI 6.42 to 31.52) and 0.84; urinary i-FABP 211, 0.64(95% CI 0.53 to 0.74), 0.73(95% CI 0.64 to 0.80), 6.35 (95%CI 3.17 to 12.72) and 0.81; urinary i-FABP/Cr 165, 0.78(95% CI 0.65 to 0.88), 0.75(95% CI 0.65 to 0.82), 6.35 (95%CI 3.17 to 12.72) and 0.81; plasma i-FABP for surgical NEC 45, 0.71(95% CI 0.51 to 0.87), 0.76(95% CI 0.50 to 0.93), 7.58 (95%CI 0.87 to 65.82) and 0.80. Plasma i-FABP is a promising biomarker in the diagnosis of NEC with high specificity and DOR; but its usefulness is limited because of medium sensitivity. The urinary i-FABP and urinary i-FABP/Cr add little value in the diagnosis. The findings were somewhat limited by the quality and small size of some of the studies included.

Elevated fecal calprotectin levels during necrotizing enterocolitis are associated with activated neutrophils extruding neutrophil extracellular traps

OBJECTIVE

Neonates with necrotizing enterocolitis (NEC) have higher calprotectin levels in stool than do healthy neonates. However, it is not known whether high stool calprotectin at the onset of bowel symptoms identifies neonates who truly have NEC vs other bowel disorders.

STUDY DESIGN

Neonates were eligible for this study when an x-ray was ordered to 'rule-out NEC'. Stool calprotectin was quantified at that time and in a follow-up stool. Each episode was later categorized as NEC or not NEC. The location of calprotectin in the bowel was determined by immunohistochemistry.

RESULTS

Neonates with NEC had higher initial and follow-up stool calprotectin levels than did neonates without NEC. Calprotectin in bowel from neonates with NEC was within neutrophil extracellular traps (NETs).

CONCLUSION

At the onset of signs concerning for NEC, fecal calprotectin is likely to be higher in neonates with NEC. Calprotectin in their stools is exported from neutrophils via NETs.

Plasma intestinal fatty acid-binding protein fails to predict endoscopic disease activity in inflammatory bowel disease patients

BACKGROUND

Monitoring disease activity in inflammatory bowel disease (IBD) is of major importance to prevent long-term complications. Intestinal fatty acid-binding protein (I-FABP) has been identified as a marker for intestinal damage and correlates with the degree of inflammation. The aim of the present study was to evaluate whether I-FABP can predict active disease or remission in Crohn's disease (CD) and ulcerative colitis (UC) in a real-life IBD cohort.

METHODS

In total, 70 patients with endoscopic disease activity available and 194 patients with disease activity on the basis of a stringent combi-score of clinical activity index, C-reactive protein, and fecal calprotectin were included. Plasma I-FABP was compared between patients with active disease and remission. In a small subgroup of CD patients, follow-up samples were analyzed.

RESULTS

In CD (139.2 vs. 119.2 pg/ml; P=0.37) and UC (107.8 vs. 151.8 pg/ml; P=0.33), the median I-FABP did not differ in endoscopic active disease versus remission. In UC patients with active disease on the basis of the combi-score, the median I-FABP (106.8 vs. 172.0 pg/ml; P=0.03) was significantly lower than in patients in remission, but not in CD (145.5 vs. 157.5 pg/ml; P=0.29). Neither disease location in CD nor extent of disease in UC influenced I-FABP significantly. I-FABP was not different (P=0.78) in CD patients with a change in disease activity over time.

CONCLUSION

Plasma I-FABP did not differ between endoscopic active disease and remission in both CD and UC. I-FABP was lower in active UC but not CD on the basis of the combi-score. On the basis of these findings, I-FABP has no potential as a novel noninvasive biomarker for disease activity in IBD.

Calprotectin: Clinical Applications in Pediatrics

As seen over the past 20 years, calprotectin has evolved as a novel, non-invasive biomarker of gastrointestinal (GI) inflammation. We present this review of calprotectin in pediatrics. This article will focus on studies using calprotectin concentrations from different body fluids to monitor inflammation in different disease states and conditions. The ultimate goal of our group is to lay down a foundation as we consider using calprotectin prospectively as a marker of intestinal inflammation that could lead to further testing and possibly a marker of preparedness for feeding. We surveyed all published studies in English of calprotectin in neonates, infants, children, and adolescents through February 2014. We will discuss calprotectin's basic properties and analysis such as characteristics, identification, presence in body fluids, and maturational development. In addition, calprotectin's use in inflammatory diseases exploring both GI and non-GI conditions will be evaluated and compared with other serum markers presently available. Finally, a summary of our findings and discussion of future work that could be undertaken in order to render calprotectin as a more useful monitoring tool to the medical research community will complete the review.

Calprotectin levels in necrotizing enterocolitis: a systematic review of the literature

BACKGROUND

Fecal calprotectin has been extensively investigated as a screening marker for the detection of necrotizing enterocolitis (NEC). However, there is a complete lack of consensus regarding its efficacy as a diagnostic test.

OBJECTIVE

The purpose of the present systematic review is to evaluate the effectiveness of fecal calprotectin as a screening marker for the detection of NEC.

MATERIALS AND METHODS

We conducted a systematic review of studies published in the Medline (1966-2016), Scopus (2004-2016), ClinicalTrials.gov (2008-2016), Cochrane Central Register of Controlled Trials CENTRAL (1999-2016), and Google Scholar (2004-2016) databases, combined with studies found in the reference lists of the included studies. All prospective and retrospective observational cohort studies were included.

RESULTS

Thirteen studies that included 601 neonates were identified in the international literature. The presence and severity of NEC was evaluated with the modified Bell's criteria. Ten studies found significantly elevated fecal calprotectin levels among infants with NEC (p < 0.05). One study found that this effect was observed irrespective of the stage of the disease. Five studies evaluated the efficacy of fecal calprotectin as a diagnostic test. The reported sensitivity ranged between 76 and 100 %, and the specificity varied from 39 to 96.4 %. However, the proposed cut-off values were not similar.

CONCLUSION

Current evidence suggests that fecal calprotectin is elevated in newborns suffering from NEC. However, its significance as an early screening marker remains unknown. Future studies are needed and should focus on the identification of specific cut-off values.

Clinical significance of FABP2 expression in newborns with necrotizing enterocolitis

BACKGROUND

This meta-analysis aimed to determine the role of human fatty acid binding protein 2 (FABP2) expression in the diagnosis of necrotizing enterocolitis (NEC) of newborns.

DATA SOURCES

Eligible studies for further statistical analysis were identified from various databases including PubMed, Expert Medica Database, Web of Science, Cochrane Library, Google Scholar, China BioMedicine and China National Knowledge Infrastructure. Random effects model was used, and summary standardized mean difference (SMD) with its 95% confidence interval (CI) was calculated to assess the association of FABP2 expression and NEC.

RESULTS

Ten articles which included 572 infants (262 infants with NEC and 310 healthy controls) were included in the current meta-analysis. FABP2 showed a positive relationship with NEC of newborns (SMD=2.88, 95% CI=2.09-3.67, P<0.001). And FABP2 expression was higher in patients with advanced stage of NEC (stage III or stage II+III) than in those with early stage of NEC (stage I) (SMD=-0.48, 95% CI=-0.87 to -0.09, P=0.015). Ethnicity-stratified analysis yielded significantly different estimates with a high FABP2 expression in NEC in both Caucasians (SMD=3.16, 95% CI=1.90-4.43, P<0.001) and Asians (SMD=2.57, 95% CI=1.50-3.64, P<0.001). Sample-based subgroup analysis showed that FABP2 expression was positively correlated with neonatal NEC in both urinary- and blood-sample subgroups (all P<0.05).

CONCLUSION

The results prove that the high FABP2 expression is related to the damage to intestinal cells, which may be a possible early detection marker identifying neonatal NEC.

Small intestinal lactoferrin and calprotectin levels in different stages of necrotizing enterocolitis in a rat model

PURPOSE

Necrotizing enterocolitis (NEC) is a severe disease of mostly premature infants with high morbidity and mortality rates. There is no reliable biomarker for detecting newborns at risk for NEC development. We aimed to investigate small intestinal lactoferrin (LF) and calprotectin (CAL) levels as predictors and indicators of disease severity in an experimental newborn rat model.

MATERIALS AND METHODS

Newborn pups were randomly divided into two groups, NEC and control. The NEC group pups were decapitated on the second, third and fourth days of the experiment for an assessment of the different stages of NEC. In the study group, hypoxia-reoxygenation model used to induce NEC. As biochemical parameters, small intestinal LF and CAL levels were measured with an enzyme-linked immunosorbent assay technique and intestinal injury scoring was evaluated as a pathologic parameter.

RESULTS

Small intestinal levels of both LF and CAL increased in the second and the third day groups, but began to decrease by the fourth day. The first, second and third day levels of LF and CAL were higher than controls. The intestinal injury scores of all NEC groups were significantly higher than the control group.

CONCLUSION

Small intestinal lactoferrin and calprotectin were good markers for demonstrating NEC. However, instead of spot testing, monitoring the levels of these markers may be more informative.

Low Abdominal NIRS Values and Elevated Plasma Intestinal Fatty Acid-Binding Protein in a Premature Piglet Model of Necrotizing Enterocolitis

To identify early markers of necrotizing enterocolitis (NEC), we hypothesized that continuous abdominal near-infrared spectroscopy (A-NIRS) measurement of splanchnic tissue oxygen saturation and intermittent plasma intestinal fatty-acid binding protein (pI-FABP) measured every 6 hours can detect NEC prior to onset of clinical symptoms. Premature piglets received parenteral nutrition for 48-hours after delivery, followed by enteral feeds every three hours until death or euthanasia at 96-hours. Continuous A-NIRS, systemic oxygen saturation (SpO₂), and heart rate were measured while monitoring for clinical signs of NEC. Blood samples obtained at 6-hour intervals were used to determine pI-FABP levels by ELISA. Piglets were classified as fulminant-NEC (f-NEC), non-fulminant-NEC (nf-NEC) and No-NEC according to severity of clinical and histologic features. Of 38 piglets, 37% (n=14) developed nf-NEC, 18% (n=7) developed f-NEC and 45% (n=17) had No-NEC. There were significant differences in baseline heart rate (p=0.008), SpO₂ (p<0.001) and A-NIRS (p<0.001) among the three groups. A-NIRS values of NEC piglets remained lower throughout the study with mean for f-NEC of 69±3.8%, 71.9±4.04% for nf-NEC, and 78.4±1.8% for No-NEC piglets (p<0.001). A-NIRS <75% predicted NEC with 97% sensitivity and 97% specificity. NEC piglets demonstrated greater variability from baseline in A-NIRS than healthy piglets (10.1% vs. 6.3%; p=0.04). Mean pI-FABP levels were higher in animals that developed NEC compared to No-NEC piglets (0.66 vs. 0.09 ng/mL;p<0.001). In f-NEC piglets, pI-FABP increased precipitously after feeds (0.04 to 1.87 ng/mL;p<0.001). pI-FABP levels increased in parallel with disease progression and a value >0.25ng/mL identified animals with NEC (68% sensitivity and 90% specificity). NIRS is a real-time, non-invasive tool that can serve as a diagnostic modality for NEC. In premature piglets, low A-NIRS in the early neonatal period and increased variability during initial feeds are highly predictive of NEC, which is then confirmed by rising plasma I-FABP levels. These modalities may help identify neonates with NEC prior to clinical manifestations of disease.

Urine biomarkers for necrotizing enterocolitis

Necrotizing enterocolitis (NEC) remains a significant cause of morbidity and mortality in premature neonates. Despite decades of investigation, treating clinicians are still not able to determine which premature infants are at greatest risk of developing NEC and which of the affected infants will develop severe NEC requiring operation. A biomarker is a specific molecular indicator that can be used to identify or measure the progress of a disease. Many potential biomarkers have been studied for their potential relevance to NEC. Those showing promise include C-reactive protein, intestinal fatty acid-binding protein, platelet-activating factor and many others. None to date have achieved sufficient predictive value to be clinically useful. Distinguishing between the specific changes in NEC and the non-specific inflammation of sepsis has proven challenging. Urine is a particularly attractive site for potential biomarkers. It can be collected readily and non-invasively, and it is a rich source of both proteins and peptides. Preliminary work has revealed some promising biomarkers of NEC in urine. Combined with clinical data, they have been shown to be highly predictive in small series of patients. Advances in high-throughput molecular analysis have opened the door to finding biomarkers that may meaningfully improve the outcome of infants at risk for NEC.

Intestinal fatty acid-binding protein as a diagnostic marker for complicated and uncomplicated necrotizing enterocolitis: a prospective cohort study

Background

Early NEC symptoms are non-specific and diagnostic tests lack discriminative power. Intestinal fatty acid-binding protein (I-FABP), mainly located in small bowel enterocytes, is released into the blood following NEC-associated enterocyte disruption. Aim of this prospective cohort trial was to determine the diagnostic value of I-FABP measured in plasma (I-FABPp) and urine (I-FABPu) for the presence of NEC, to evaluate I-FABP levels during NEC development, and to assess its prognostic value for the progression from suspected to complicated disease.

Methods

Between 2010 and 2012 we prospectively enrolled neonates with suspected NEC. We measured I-FABP levels eight-hourly from onset of suspected NEC for at least 48 hours, or until surgery. NEC diagnosis was confirmed radiologically or during operation. We defined NEC as complicated if it resulted in surgery and/or death. We determined disease course and diagnostic I-FABP cut-off points.

Results

The study comprised 37 neonates (24M, 13F), gestational age 28 (24–36) weeks, birth weight 1190 (570–2,400) grams. We found significantly higher I-FABPp and I-FABPu levels in NEC patients (n = 22) than in patients with other diagnoses (n = 15). Cut-off values for diagnosing NEC were 9 ng/mL I-FABPp and 218 ng/mL I-FABPu, with corresponding likelihood ratios (LRs) of 5.6 (95% CI 0.89–35) and 5.1 (95% CI 0.73–36), respectively. I-FABP levels were highest in the first eight hours after symptom onset and gradually decreased over time. Cut-off values for complicated disease were 19 ng/mL I-FABPp and 232 ng/mL I-FABPu, with LRs of 10 (95% CI 1.6–70) and 11 (95% CI 1.6–81), respectively.

Conclusions

Both plasma and urinary I-FABP levels specifically identify NEC in preterm infants prior to appearance of diagnostic radiological signs suggestive for NEC. Moreover, serial I-FABP measurements accurately predict development of complicated disease.

Necrotizing enterocolitis: a clinical review on diagnostic biomarkers and the role of the intestinal microbiota

Necrotizing enterocolitis (NEC) remains one of the most frequent gastrointestinal diseases in the neonatal intensive care unit, with a continuing unacceptable high mortality and morbidity rates. Up to 20% to 40% of infants with NEC will need surgical intervention at some point. Although the exact pathophysiology is not yet elucidated, prematurity, use of formula feeding, and an altered intestinal microbiota are supposed to induce an inflammatory response of the immature intestine. The clinical picture of NEC has been well described. However, an early diagnosis and differentiation against sepsis is challenging. Besides, it is difficult to timely identify NEC cases that will deteriorate and need surgical intervention. This may interfere with the most optimal treatment of infants with NEC. In this review, we discuss the pathogenesis, diagnosis, and treatment of NEC with a focus on the role of microbiota in the development of NEC. An overview of different clinical prediction models and biomarkers is given. Some of these are promising tools for accurate diagnosis of NEC and selection of appropriate therapy.

Noninvasive biomarkers of necrotizing enterocolitis

Necrotizing enterocolitis is an acute inflammatory disease, which primarily affects preterm infants, and is a leading cause of morbidity and mortality in the neonatal intensive care unit. Unfortunately, necrotizing enterocolitis can be difficult to distinguish from other diseases and clinical conditions especially during the early course of the disease. This diagnostic uncertainty is particularly relevant to clinical evaluation and medical management and potentially leads to unnecessary and extended periods of cessation of enteral feedings and prolonged courses of parenteral nutrition and antibiotics. Biomarkers are molecular indicators of a disease process, diagnosis, prognosis and can be used to monitor the effects of disease management. Historically, there has been a paucity of reliable and robust biomarkers for necrotizing enterocolitis. However, several studies have recently identified promising biomarkers. Noninvasive samples for biomarker measurement are preferred and may have certain advantages in the preterm infant. In this review article, we focus on recent exciting and promising discoveries in noninvasive biomarkers for necrotizing enterocolitis.

Stooling pattern and early nutritional exposures associated with necrotizing enterocolitis in premature infants

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency affecting premature infants. A better understanding of the clinical signs and symptoms associated with the disease may result in an improved ability to more effectively intervene in patient care. One of the clinical signs that have not been fully explored is the stooling pattern of preterm infants. This retrospective case-control study included 258 premature infants born prior to 29 weeks of gestation: 129 infants with NEC and 129 gestational age-matched controls. Data were collected from the medical record for the first 28 postnatal days. The relationships between the stooling pattern of premature infants and NEC were assessed via nonparametric techniques and linear mixed models. We identified few differences in the stooling pattern among infants with NEC and their unaffected counterparts. During the first week following birth, infants with NEC passed stool more frequently than controls. However, we found that these infants were taking nothing by mouth for fewer days in the first week following birth compared with controls. We also found that infants who developed NEC were fed smaller proportions of breast milk than healthy controls. Aberrant gut motility has been associated with prematurity and inflammatory bowel disease. However, our analyses did not identify any major differences in the stooling pattern among NEC case patients and controls. While further analyses may be needed, clinical suspicion for NEC should not be overwhelmingly influenced by the stooling pattern observed during the early neonatal period.

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.

Fecal calprotectin concentration in neonatal necrotizing enterocolitis

PURPOSE

Among the many factors associated with acute intestinal mucosal infection, numerous studies have proposed the usefulness of fecal calprotectin. The aim of this study was to evaluate the usefulness of fecal calprotectin in the diagnosis of necrotizing enterocolitis (NEC).

METHODS

We collected 154 stool samples from 16 very low birth weight and premature newborns at the Konyang University Hospital neonatal intensive care unit or neonatal nursery. The stool samples were collected using the Calprest device, and the fecal calprotectin level was measured with the BÜHLMANN Calprotectin enzyme-linked immunosorbent assay kit.

RESULTS

Fecal calprotectin levels were significantly higher in the NEC group than in the non-NEC group (P=0.02). There was a significant positive linear relationship between the fecal calprotectin level and number of days after birth (P=0.00) in the gestational age <26 weeks group. There was a significant negative linear relationship between the calprotectin level and number of days after birth (P=0.03) in the gestational age ≥26 weeks and <30 weeks group. There was no difference in the calprotectin levels according to the type and method of feeding between the NEC and non-NEC groups.

CONCLUSION

Fecal calprotectin levels were significantly increased in premature infants with NEC. The fecal calprotectin test is a noninvasive, easy, and useful tool for the diagnosis of NEC.

A novel urine peptide biomarker-based algorithm for the prognosis of necrotising enterocolitis in human infants

OBJECTIVE

Necrotising enterocolitis (NEC) is a major source of neonatal morbidity and mortality. The management of infants with NEC is currently complicated by our inability to accurately identify those at risk for progression of disease prior to the development of irreversible intestinal necrosis. We hypothesised that integrated analysis of clinical parameters in combination with urine peptide biomarkers would lead to improved prognostic accuracy in the NEC population.

DESIGN

Infants under suspicion of having NEC (n=550) were prospectively enrolled from a consortium consisting of eight university-based paediatric teaching hospitals. Twenty-seven clinical parameters were used to construct a multivariate predictor of NEC progression. Liquid chromatography/mass spectrometry was used to profile the urine peptidomes from a subset of this population (n=65) to discover novel biomarkers of NEC progression. An ensemble model for the prediction of disease progression was then created using clinical and biomarker data.

RESULTS

The use of clinical parameters alone resulted in a receiver-operator characteristic curve with an area under the curve of 0.817 and left 40.1% of all patients in an 'indeterminate' risk group. Three validated urine peptide biomarkers (fibrinogen peptides: FGA1826, FGA1883 and FGA2659) produced a receiver-operator characteristic area under the curve of 0.856. The integration of clinical parameters with urine biomarkers in an ensemble model resulted in the correct prediction of NEC outcomes in all cases tested.

CONCLUSIONS

Ensemble modelling combining clinical parameters with biomarker analysis dramatically improves our ability to identify the population at risk for developing progressive NEC.

Accurate prediction of anastomotic leakage after colorectal surgery using plasma markers for intestinal damage and inflammation

BACKGROUND

Anastomotic leakage is a frequent and life-threatening complication after colorectal surgery. Early recognition of anastomotic leakage is critical to reduce mortality. Because early clinical and radiologic signs of anastomotic leakage are often nonspecific, there is an urgent need for accurate biomarkers. Markers of inflammation and gut damage might be suitable, as these are hallmarks of anastomotic leakage.

STUDY DESIGN

In 84 patients undergoing scheduled colorectal surgery with primary anastomosis, plasma samples were collected preoperatively and daily after surgery. Inflammatory markers, C-reactive protein; calprotectin; and interleukin-6, and intestinal damage markers, intestinal fatty acid binding protein; liver fatty acid binding protein; and ileal bile acid binding protein, were measured. Diagnostic accuracy of single markers or combinations of markers was analyzed by receiver operating characteristic curve analysis.

RESULTS

Anastomotic leakage developed in 8 patients, clinically diagnosed at median day 6. Calprotectin had best diagnostic accuracy to detect anastomotic leakage postoperatively. Highest diagnostic accuracy was obtained when C-reactive protein and calprotectin were combined at postoperative day 3, yielding sensitivity of 100%, specificity of 89%, positive likelihood ratio = 9.09 (95% CI, 4.34-16), and negative likelihood ratio = 0.00 (95% CI, 0.00-0.89) (p < 0.001). Interestingly, preoperative intestinal fatty acid binding protein levels predicted anastomotic leakage at a cutoff level of 882 pg/mL with sensitivity of 50%, specificity of 100%, positive likelihood ratio = infinite (95% CI, 4.01-infinite), and negative likelihood ratio = 0.50 (95% CI, 0.26-0.98) (p < 0.0001).

CONCLUSIONS

Preoperative intestinal fatty acid binding protein measurement can be used for anastomotic leakage risk assessment. In addition, the combination of C-reactive protein and calprotectin has high diagnostic accuracy. Implementation of these markers in daily practice deserves additional investigation.

Urinary intestinal fatty acid binding protein predicts necrotizing enterocolitis

Necrotizing enterocolitis, characterized by sudden onset and rapid progression, remains the most significant gastrointestinal disorder among premature infants. In seeking a predictive biomarker, we found intestinal fatty acid binding protein, an indicator of enterocyte damage, was substantially increased within three and seven days before the diagnosis of necrotizing enterocolitis.

Stool calprotectin in necrotizing enterocolitis

Background:

Calprotectin is a 36 kDa protein present in the cytoplasm of the neutrophil has antimicrobial and apoptosis inducing activities. In vitro studies have shown that calprotectin inhibits the growth of various microorganisms. Necrotizing enterocolitis (NEC) remains one of the leading causes of morbidity and mortality in neonatal intensive care units (NICU), affecting up to 5% of premature infants. Fecal calprotectin is resistant to degradation and has been proposed as a useful marker of gastrointestinal inflammation.

Objective:

The objective of the present study is to evaluate fecal calprotectin concentrations in NEC.

Study Design:

Fifteen neonates with a clinical diagnosis of NEC were studied; they admitted at NICU of Zagazig University Hospital. In addition, 20 age sex matched neonates fed all caloric requirement served as the control group. All neonates were subjected to history taking, clinical examination, laboratory investigations (complete blood count, C-reactive protein) and determination of stool calprotectin.

Results:

There was a highly significant increase in fecal calprotectin in patients than control and there was a highly significant increase in its fecal level in died patients than living one. Also significant increase in fecal calprotectin level with increasing severity of NEC.

Conclusion:

Fecal calprotectin measurements could be a valuable tool for the investigation of preterm and full term infants suspected of having NEC.

Urine protein biomarkers for the diagnosis and prognosis of necrotizing enterocolitis in infants

OBJECTIVES

To test the hypothesis that an exploratory proteomics analysis of urine proteins with subsequent development of validated urine biomarker panels would produce molecular classifiers for both the diagnosis and prognosis of infants with necrotizing enterocolitis (NEC).

STUDY DESIGN

Urine samples were collected from 119 premature infants (85 NEC, 17 sepsis, 17 control) at the time of initial clinical concern for disease. The urine from 59 infants was used for candidate biomarker discovery by liquid chromatography/mass spectrometry. The remaining 60 samples were subject to enzyme-linked immunosorbent assay for quantitative biomarker validation.

RESULTS

A panel of 7 biomarkers (alpha-2-macroglobulin-like protein 1, cluster of differentiation protein 14, cystatin 3, fibrinogen alpha chain, pigment epithelium-derived factor, retinol binding protein 4, and vasolin) was identified by liquid chromatography/mass spectrometry and subsequently validated by enzyme-linked immunosorbent assay. These proteins were consistently found to be either up- or down-regulated depending on the presence, absence, or severity of disease. Biomarker panel validation resulted in a receiver-operator characteristic area under the curve of 98.2% for NEC vs sepsis and an area under the curve of 98.4% for medical NEC vs surgical NEC.

CONCLUSIONS

We identified 7 urine proteins capable of providing highly accurate diagnostic and prognostic information for infants with suspected NEC. This work represents a novel approach to improving the efficiency with which we diagnose early NEC and identify those at risk for developing severe, or surgical, disease.

Intestinal fatty acid-binding protein in neonates with imminent necrotizing enterocolitis

BACKGROUND

Intestinal fatty acid-binding protein (I-FABP) is a promising marker for necrotizing enterocolitis (NEC). It can be measured in plasma (I-FABPp) and urine (I-FABPu). Data on the best way to measure I-FABP (in plasma or urine) and the necessity of simultaneous measurement of the urinary creatinine concentration to correct for physiological variations in urine concentration are not available. This holds also true for the reciprocal relation between I-FABPp, I-FABPu and other more conventional laboratory parameters.

OBJECTIVES

To evaluate the above-mentioned correlations of I-FABP measurements in neonates with suspected NEC.

METHODS

All neonates with suspected NEC were prospectively included. I-FABPp and I-FABPu were analyzed at regular intervals during the first 24 h after onset of symptoms. Correlation and agreement were assessed between these and other parameters (i.e., IL-6, WBC, platelet count, CRP, pH and lactate).

RESULTS

Included were 24 boys, 13 girls [median (range) GA 28 weeks (24-36), median birth weight 1,190 g (570-2,400)]. I-FABPu correlated strongly with I-FABPp (r 0.80, p < 0.001) with an adequate agreement. A very strong correlation between I-FABPu and I-FABPu/urine creatinine ratio (r 0.98, p < 0.001) existed. Correlations between I-FABPp/u and conventional parameters were moderate to strong until 8 h after onset of symptoms.

CONCLUSION

In neonates with suspected NEC, I-FABPu correlates strongly with I-FABPp, offering an opportunity to choose the most appropriate way of measuring I-FABP. Calculating urinary IFABP/creatinine ratio seems redundant. Moderately strong correlations between I-FABPu and IL-6, WBC and lactate were found.