Stool calprotectin in necrotizing enterocolitis

Markers of Intestinal Permeability and Inflammation in Enterally Fed Children with Cerebral Palsy

Cerebral palsy (CP) results in non-progressive damage to the central nervous system, leading to functional disorders of the gastrointestinal tract and requiring enteral nutrition via gastrostomy in some patients. The aim of the study was to assess the impact of enteral nutrition on intestinal inflammation expressed by stool calprotectin and intestinal permeability determined by fecal zonulin and IFABP, and to determine whether CP affects these parameters. The study group consisted of 30 children with CP, fed enterally (Cerebral Palsy Enteral Nutrition-CPEN), and two reference groups: 24 children with CP, fed orally with a standard diet (CPC-Cerebral Palsy Controls) and 24 healthy children (HC-healthy controls). The differences between these groups and between the combined CP groups (CPG and CPEN + CPC) and HC were analyzed. Fecal zonulin, calprotectin, and intestinal fatty acid-binding protein 2 (IFABP2) levels were determined by ELISA. The concentrations of fecal calprotectin and zonulin were significantly higher in the CPEN group than in the CPC group (p = 0.012, p = 0.025). When comparing the CPG (n = 53) with the HC group (n = 24), statistically significant differences were observed for calprotectin (p = 0.000018, higher in the CPG) and IFABP (p = 0.021, higher in HC). Enteral nutrition was associated in our cohort with increased fecal calprotectin and zonulin. Children with cerebral palsy presented with increased fecal calprotectin but not increased intestinal permeability expressed by stool zonulin.

Antenatal Growth, Gestational Age, Birth, Enteral Feeding, and Blood Citrulline Levels in Very Low Birth Weight Infants

Early enteral nutrition using reliable biomarkers of intestinal function must be established to improve neurodevelopmental outcomes in very low birth weight infants (VLBWIs). Serum citrulline levels reflect the intestinal function in adults. To elucidate the relationship among antenatal growth, postnatal enteral nutrition, and blood citrulline levels, a retrospective single-center observational study was conducted on 248 VLBWIs born between April 2014 and March 2021. A mixed effect model and post hoc simple slope analysis were used to estimate the correlations between clinical variables and citrulline levels at Early (day 5.1) and Late (day 24.3) postnatal ages. Greater gestational age, birth weight, and amount of enteral nutrition at the time of blood sampling were associated with lower citrulline levels at the Early postnatal age and higher citrulline levels at the Late postnatal age. Provided that Early citrulline levels predominantly reflect the consequence of antenatal citrulline metabolism, it is suggested that fetal growth and maturation are likely to promote citrulline catabolism in utero and its synthesis after birth. With additional insights into the temporal transition point wherein the maturation-dependent balance of citrulline metabolism shifts from catabolism-dominant to synthesis-dominant, citrulline emerges as a potential biomarker for assessing intestinal function and gastrointestinal disorders.

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.

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

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

Postnatal Dynamics and Clinical Associations of Fecal Calprotectin in Very Preterm Infants: Implications for Necrotizing Enterocolitis and Feeding Intolerance

INTRODUCTION

To elucidate the postnatal dynamics and clinical associations of fecal calprotectin (FC) in very preterm infants, with a focus on necrotizing enterocolitis (NEC) and feeding intolerance (FI).

METHODS

We performed a prospective observational cohort study in infants with a gestational age of <32 weeks or birth weight <1,500 g with weekly feces collection. The relationships between FC, NEC, and FI were investigated, adjusting for demographic and clinical factors.

RESULTS

A total of 1,086 fecal samples were collected from 194 preterm infants. Postnatal FC levels of non-NEC infants were highly variable and followed an age-dependent patterned progression. FC levels were elevated in patients with NEC before and at NEC onset, distinguishing them from non-NEC infants and those at sepsis onset. Among infants without NEC or sepsis, those with FI exhibited lower FC concentrations throughout hospitalization and displayed a significant delay in reaching high FC levels after meconium compared with non-FI infants. The age to reach the first high nonmeconial FC levels was positively associated with the time to achieve full enteral feeding.

DISCUSSION

Postnatal FC dynamics among premature infants followed a patterned progression but were disturbed in patients with NEC and FI. Because of the high variations, the use of FC levels in NEC diagnosis should be implemented with caution in clinical practice. FC may help understand FI and feeding progression in very preterm infants. Further research is needed to validate these findings and explore the potential clinical applications of FC in this population.

The perinatal factors that influence the excretion of fecal calprotectin in premature-born children

This study aimed to provide additional information on the influence of perinatal factors on fecal (f)-calprotectin values in preterm infants. Calprotectin was determined from the first spontaneous stool (analyzed on the Alegria device by using the enzyme-linked immunosorbent assay [ELISA] method) obtained from neonates at a mean age of 3.41 ± 2.44 days of life. We analyzed 114 subjects who had a body weight of 1847.67 ± 418.6 g and were born at a gestational age of 32.6 ± 2.43 weeks, without intestinal and other congenital anomalies or any diseases other than those related to premature birth. The values of f-calprotectin are in a positive correlation with female subjects, intrauterine growth restriction, significant ductus arteriosus, enteral feeding intolerance, postnatal prolonged use of broad-spectrum antibiotics, and values ​​of bicarbonates (analyzed in a sample of capillary arterial blood). Measurement of f-calprotectin in the first 7 days after birth can help to early detect the intestinal distress or early staging of necrotizing enterocolitis in premature infants.

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.

[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.

New Strategies for Necrotizing Enterocolitis Diagnosis and Prevention in Newborns

Necrotizing enterocolitis is one of the most frequent and severe gastrointestinal diseases that affect preterm newborns in Neonatal Intensive Care Units. It was firstly described in 1960s, but this clinical entity was not widely recognized until the advent of modern neonatal intensive care. The disease is characterized by submucosal edema, infiltration of intestinal wall by immune cells, specifically neutrophils and, in severe forms, wall necrosis that leads to intestinal perforation. Its incidence is inversely associated to birth weight and gestational age. Necrotizing enterocolitis has been responsible for high rates of morbidity and mortality (15-30%), despite improvements made in neonatal care in the last decades. The challenge is to optimize strategies for early diagnosis, define the best medical and surgical treatments and standardize preventive measures. Several biomarkers have been proposed for the early prediction of necrotizing enterocolitis onset in preterm newborns and can be useful not only for diagnostic purposes but also for prediction of disease progression and severity. The purpose of this paper is to illustrate the most recent evidence regarding the diagnosis and prevention of necrotizing enterocolitis. This manuscript contributes to clinical decision-making in preterm neonates at high risk of developing necrotizing enterocolitis.

The Effect of Probiotics on Symptoms, Gut Microbiota and Inflammatory Markers in Infantile Colic: A Systematic Review, Meta-Analysis and Meta-Regression of Randomized Controlled Trials

Immaturity in digestive-tract motor function and altered intestinal microbiome may play roles in pathogenesis of infantile colic. We assessed the impact of probiotic therapy on crying duration day, in newborns experiencing colic attacks. The PubMed, Embase, Cinnahl, Web of Science databases, and a clinical trials registry (ClinicalTrials.gov) were searched from inception until 12/02/2020. Random-effects meta-analyses were used to derive standardized mean differences/differences in means and risk ratios. We included 16 studies, which involved 1319 newborns aged up to 6 months. Lactobacillus reuteri strain DSM17938 was administered predominantly (n = 10). Probiotic intervention reduced the duration of crying (standardized mean difference = -2.012, 95% confidence interval: -2.763 to -1.261, z = -5.25, p < 0.0001). The probability of at least a 50% reduction in crying duration was at least 1.98 times higher in the intervention group than in controls (Z = 4.80, p < 0.0001). The effects of the intervention were not significantly affected by the risk of bias assessment, percentage of breastfed infants, and duration of the study. In 11 studies, data concerning gut microbiota composition and function and/or immunological markers were given. Probiotics significantly shortened the crying duration, but a causal relationship between the modulatory effect of probiotics on microbiota and the immune system has not been confirmed.

Analysis of Faecal Zonulin and Calprotectin Concentrations in Healthy Children During the First Two Years of Life. An Observational Prospective Cohort Study

Factors affecting the intestinal-barrier permeability of newborns, such as body mass index (BMI), nutrition and antibiotics, are assumed to affect intestinal-barrier permeability in the first two years of life. This study assessed 100 healthy, full-term newborns to 24 months old. Faecal zonulin/calprotectin concentrations were measured at 1, 6, 12, 24 months as gut-permeability markers. Zonulin concentrations increased between 1 and 12 months (medians: 114.41, 223.7 ng/mL; respectively), whereas calprotectin concentrations decreased between one and six months (medians: 149. 29, 109.28 µg/mL); both then stabilized (24 months: 256.9 ng/mL zonulin; 59.5 µg/mL calprotectin). In individual children, high levels at one month gave high levels at older ages (correlations: calprotectin: between 1 and 6 or 12 months: correlation coefficient (R) = 0.33, statistical significance (p) = 0.0095; R = 0.28, p = 0.032; zonulin: between 1 and 24 months: R = 0.32; p = 0.022, respectively). Parameters which gave marker increases: antibiotics during pregnancy (calprotectin; six months: by 80%, p = 0.038; 12 months: by 48%, p = 0.028); vaginal birth (calprotectin: 6 months: by 140%, p = 0.005); and > 5.7 pregnancy-BMI increase (zonulin: 12 months: by 74%, p = 0.049). Conclusions: “Closure of the intestines” is spread over time and begins between the sixth and twelfth month of life. Antibiotic therapy, BMI increase > 5.7 during pregnancy and vaginal birth are associated with increased intestinal permeability during the first two years of life. Stool zonulin and calprotectin concentrations were much higher compared with previous measurements at older ages; clinical interpretation and validation are needed (no health associations found).

Recent Potential Noninvasive Biomarkers in Necrotizing Enterocolitis

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

Enteric dysbiosis and fecal calprotectin expression in premature infants

BACKGROUND

Premature infants often develop enteric dysbiosis with a preponderance of Gammaproteobacteria, which has been related to adverse clinical outcomes. We investigated the relationship between increasing fecal Gammaproteobacteria and mucosal inflammation, measured by fecal calprotectin (FC).

METHODS

Stool samples were collected from very-low-birth weight (VLBW) infants at ≤2, 3, and 4 weeks' postnatal age. Fecal microbiome was surveyed using polymerase chain reaction amplification of the V4 region of 16S ribosomal RNA, and FC was measured by enzyme immunoassay.

RESULTS

We enrolled 45 VLBW infants (gestation 27.9 ± 2.2 weeks, birth weight 1126 ± 208 g) and obtained stool samples at 9.9 ± 3, 20.7 ± 4.1, and 29.4 ± 4.9 days. FC was positively correlated with the genus Klebsiella (r = 0.207, p = 0.034) and its dominant amplicon sequence variant (r = 0.290, p = 0.003), but not with the relative abundance of total Gammaproteobacteria. Klebsiella colonized the gut in two distinct patterns: some infants started with low Klebsiella abundance and gained these bacteria over time, whereas others began with very high Klebsiella abundance.

CONCLUSION

In premature infants, FC correlated with relative abundance of a specific pathobiont, Klebsiella, and not with that of the class Gammaproteobacteria. These findings indicate a need to define dysbiosis at genera or higher levels of resolution.

Intestinal Microbiota in Hirschsprung Disease

OBJECTIVES

The aim of the study was to characterize the microbiota profiles of patients with Hirschsprung disease (HD) and to evaluate this in relation to postoperative bowel function and the incidence of Hirschsprung-associated enterocolitis (HAEC).

METHODS

All patients operated on for HD at our center between 1987 and 2011 were invited to answer questionnaires on bowel function and to participate in a clinical follow-up for laboratory investigations, including fecal DNA extraction, fecal calprotectin (FC), and brush border lactase (LCT) genotyping. The microbiota compositions of patients with HD were compared with those of healthy controls aged between 2 and 7 years.

RESULTS

The microbiota composition of eligible patients with HD (n = 34; median age 12 [range, 3-25] years) differed from the healthy controls (n = 141), showing decreased overall microbial richness (P < 0.005). Seventy-seven percent had experienced HAEC. Normal maturation of the intestinal flora was not observed, but patients had a significantly increased abundance of Proteobacteria among other taxa (P < 0.005) resulting in a reduced carbohydrate degradation potential, as predicted by the taxonomic composition. Genetic lactase deficiency was present in 17% and did not correlate with bowel symptoms. No patients reported active HAEC at the time of sampling and FC was within the normal range in all samples.

CONCLUSIONS

Patients with HD and HAEC had a significantly altered intestinal microbiome compared to healthy individuals, characterized by a lack of richness and pathologic expansions of taxa, particularly Enterobacteria and Bacilli. Further evaluation is needed to identify whether these observations are intrinsic to HD or secondary to the recurrent use of antibiotics during early childhood.

Point-of-Care Fecal Calprotectin Monitoring in Preterm Infants at Risk for Necrotizing Enterocolitis

OBJECTIVE

To establish baseline trends in fecal calprotectin, a protein excreted into the stool when there is neutrophilic inflammation in the bowel, in infants at risk for necrotizing enterocolitis (NEC).

STUDY DESIGN

We performed a prospective observational cohort study in infants with a birth weight of <1500 g without existing bowel disease at a level IV neonatal intensive care unit from October 2015 to September 2016. Stools were collected once daily for 30 days or until 32 weeks postmenstrual age and processed using the Fecal Calprotectin High Range Quantitative Quantum Blue assay.

RESULTS

In 64 preterm infants, during the first week after birth, 62% of infants had an initial stool sample with high baseline calprotectin levels (≥200 µg/g). In assessment of maternal and neonatal risk factors, maternal etiology for preterm birth (ie, eclamplsia or preeclampsia) was the only significant factor associated with high baseline calprotectin level. Two patients in the cohort developed NEC. Calprotectin levels for the entire cohort fluctuated during the observed period but generally increased in the third and fourth weeks after birth.

CONCLUSIONS

At-risk infants had highly variable fecal calprotectin levels, with maternal causes for preterm birth associated with higher baseline levels. More longitudinal data in infants with NEC are necessary to determine whether acute rises in fecal calprotectin levels prior to clinical diagnosis can be confirmed as a diagnostic or prognostic biomarker.

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.

Delivery and feeding mode affects fecal calprotectin levels in infants <7months old

BACKGROUND

Elevated fecal calprotectin (FC) is a non-invasive marker of inflammation indicating bowel disease. However, healthy infants have displayed high FC levels, with large variation. We sought to determine what factors might affect FC levels in children <6months old.

METHODS

We recruited 133 healthy infants aged 0-6months from four Korean day care centers. Stool samples were analyzed by immunosorbent assay. All infants completed a questionnaire related to clinical characteristics including birth and feeding history.

RESULTS

The mean FC concentration of all of participants was 237.40μg/g (range 11.5-1330.6μg/g). FC levels between 0 and 6months reduced with increasing age and the differences were statistically significant. The mean FC value according to feeding mode was 354.67μg/g for those fed breast milk and 149.44μg/g for those fed formula milk (p<0.001). Mean FC values were 319.69μg/g vs. 130.97μg/g for normal spontaneous vaginal delivery (NSVD) vs. caesarean section births, respectively (p<0.001). In addition, delivery mode affected the FC level at 0-6months regardless of feeding mode.

CONCLUSION

The FC levels of infants aged 0-6months reduced with age and were higher than the normal levels observed in healthy older infants. The FC value at <7months was higher in infants who were fed breast milk and born by NSVD.

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.

Fecal calprotectin levels in preterm infants with and without feeding intolerance

OBJECTIVES

To assess the level of fecal calprotectin in preterm neonates with feeding intolerance, as well as to evaluate it as a marker of feeding intolerance and to determine a cut-off level of fecal calprotectin in feeding intolerance.

METHODS

Analytical, multicenter, case-control study, which was carried out in neonatal intensive care units in Egypt, in a period from August 1, 2014 to March 1, 2015 on 52 preterm neonates. Neonates were classified into two groups; a study group including 26 neonates who met inclusion criteria and a control group including 26 neonates for comparison.

RESULTS

Fecal calprotectin levels ranged from 3.9μg/g to 971.8μg/g, and there was a significant increase in fecal calprotectin in the study group when compared to the control group (334.3±236.6μg/g vs. 42.0±38.2μg/g, respectively) with moderate inverse significant correlation between fecal calprotectin and birth weight. Furthermore, there was moderate, significant correlation between fecal calprotectin and duration of breastfeeding range. On the other hand, there was no correlation between fecal calprotectin and post-natal age, gestational age, or volume of feeding. A cut-off at the 67.0μg/g level, with 100.0% sensitivity and 76.9% specificity, was considered.

CONCLUSION

Fecal calprotectin level increased significantly in neonates with feeding intolerance; it can be used to detect early cases with necrotizing enterocolitis in neonates, but this subject still needs more investigations on more patients.

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.

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.

Routine fecal occult blood testing does not predict necrotizing enterocolitis in very low birth weight neonates

OBJECTIVE

To determine sensitivity, specificity, predictive value of routine fecal occult blood (FOB) testing on the identification of Bell's Stage II or III necrotizing enterocolitis (NEC) in very low birth weight (VLBW) infants.

METHODS

Retrospective medical record review of VLBW infants from 2012- 2013 evaluating FOB results and clinical and demographic risk factors. We determined predictive values of positive FOB testing within 48 hours of definite NEC diagnosis. We performed logistic regression analyses for predictors of NEC and for predictors of having positive FOB during NICU admission.

RESULTS

The incidence of NEC in our cohort of 203 infants was 3.9% (n = 8). None had positive FOB results within 48 hours of diagnosis, and only 12.5% had any positive FOB within 7 days. Sensitivity of positive FOB for predicting definite NEC = 0%, specificity = 34.4%, and positive predictive value = 0%. A majority of VLBWs (67.0%) had > one positive FOB result during their NICU course. On logistic regression, intrauterine growth restricted (IUGR) infants had significantly higher odds of both developing NEC and of having positive FOB. Positive FOB was not a significant predictor of NEC. Those with lower birth gestational ages had higher odds of positive FOB.

CONCLUSIONS

Positive FOB testing occurred in a majority of VLBW infants, with higher odds in the more preterm and IUGR. However, the sensitivity, specificity, and predictive value of routine FOB testing for identifying NEC were all very poor. Our data demonstrates that this test offers no advantages in the early diagnosis of NEC.

Relationships of Feeding and Mother's Own Milk with Fecal Calprotectin Levels in Preterm Infants

OBJECTIVE

To describe longitudinal effects of feeding volume and type of milk on fecal calprotectin (f-CP) in very low-birth weight (VLBW) infants.

STUDY DESIGN

Prospective data were collected across Neonatal Intensive Care Unit (NICU) admission for 6 weeks or until discharge in 75 VLBW neonates. The mean gestational age on entry into the study was 29 weeks.

RESULTS

Seventy-four (99%) mothers provided expressed milk in varying amounts. Twenty-three mothers (31%) provided exclusive mother's own milk (MOM) throughout. Preterm infant formula (PIF) and pasteurized donor milk were added to feedings of remaining infants. Pooled MOM was analyzed weekly for levels of a panel of cytokines, chemokines, and growth factors, and secretory Immunoglobulin A (sIgA) so that the exact amount of exposure to the gut of these milk bioactives could be estimated. f-CP levels ranged from 160 to 350 μg/g stool. Total feeding volume was positively associated with f-CP, controlling for infant weight, and f-CP levels rose across time. Exclusive MOM feedings for the entire measurement period were associated with rising levels of f-CP, but mixed feedings (MOM with added PIF or pasteurized donor milk (PDM) did not show this increase over time.

CONCLUSION

The presence of f-CP may represent a response to milk volumes and MOM, which represents normal development rather than always implicating pathological inflammation in the VLBW infant.