Biomarkers of necrotising enterocolitis

Targeted LC-MS/MS profiling of bile acids reveals primary/secondary bile acid ratio as a novel biomarker for necrotizing enterocolitis

Bile acids (BAs) are involved in the development of necrotizing enterocolitis (NEC), which mainly occurs in preterm infants. We aim to identify the change of BAs in preterm infants and validate its potential value in the detection of NEC. Targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed to measure the plasma BAs in healthy preterm infants and patients with NEC. By analyzing the level of BAs in healthy preterm infants, we found that the plasma concentrations of BAs were related to sex, gestational/postnatal age, birth weight, mode of birth, and feeding type after birth. The plasma levels of TCA, GCA, TCDCA, GCDCA, primary BAs, and total BAs and the primary/secondary BA ratio were decreased, while DCA, UDCA, and secondary BAs were increased in NEC. The primary/secondary BA ratio (cutoff point 62.9) can effectively differentiate NEC from healthy preterm infants, with an AUC of 0.9, a sensitivity of 94.5%, and a specificity of 78.1%. Combining the ratio with high-risk factors of NEC can better distinguish between NEC and control, with an AUC of 0.95. Importantly, significantly lower levels of primary/secondary BA ratio were found in infants with surgical NEC than in nonsurgical NEC cases. The cutoff point of 28.7 identified surgical NEC from nonsurgical NEC with sensitivity and specificity of 76.9% and 100%. Thus, our study identified that the primary/secondary BA ratio in the plasma can differentiate NEC from healthy preterm infants and effectively differentiate the surgical NEC from nonsurgical NEC. Therefore, LC-MS/MS was expected to be a novel measurement platform used to distinguish infants who are most in need of close monitoring or early surgical intervention.

Describing patterns in serum creatinine in infants with and without necrotizing enterocolitis

OBJECTIVE

To evaluate serum creatinine (SCr) patterns and the development of acute kidney injury (AKI), as potential biomarkers of necrotizing enterocolitis (NEC).

STUDY DESIGN

Retrospective chart review of preterm infants with and without NEC born 23-32 weeks gestation admitted to Nationwide Children's Hospital NICU. Medical versus surgical NEC was determined by radiographic and clinical findings. Available inpatient SCr levels obtained on days 8 through 365 were included.

RESULT

In this cohort, 77 NEC and a randomly selected group of 82 non-NEC infants met inclusion criteria. Fifteen of the 70 (21.4%) with NEC met criteria for AKI versus 0 of 43 (0.0%) without NEC. One of the 13 with AKI had AKI within 7 days prior to NEC diagnosis (7.7%).

CONCLUSION

AKI is more prevalent in infants with NEC. The temporal association between AKI and NEC could not be evaluated due to inconsistent SCr surveillance and should be evaluated in future studies.

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 for CCR9+ IL-17+ Regulatory T Cell as a Predictor of Early Necrotizing Enterocolitis

BACKGROUND

Circulating CCR9+ IL-17+ regulatory T (Treg) cells and intestinal barrier biomarkers, such as trefoil factor 3 (TFF3), intestinal-fatty acid binding protein (I-FABP), and Zonulin, are associated with gastrointestinal inflammatory diseases. So far, it is still difficult for clinicians to predict early necrotizing enterocolitis (NEC).

STUDY DESIGN

This study included 13 patients with stage I NEC-like presentation (early NEC), 24 patients with one stage of II or III NEC (confirmed NEC), and 80 non-NEC and nonsepsis preterm infants (control group). Another 16 patients experienced at least two stages. We used flow cytometry to measure the frequency of CCR9+ IL-17+ Treg cells and enzyme-linked immunosorbent assay to measure TFF3, I-FABP, and Zonulin levels in the peripheral blood.

RESULTS

The demographic and clinical characteristics of patients were comparable. Compared with controls, CCR9+ IL-17+ Treg cells were markedly increased in early NEC and slightly increased in confirmed NEC; in contrast, plasma TFF3, I-FABP, and Zonulin concentrations were notably elevated in confirmed NEC and slightly elevated or not elevated in early NEC. Moreover, for patients who experienced at least two stages, dynamic monitoring of the above indicators also verified this.

CONCLUSIONS

This study suggested that an elevated frequency of circulating CCR9+ IL-17+ Treg cells could be a predictor of intestinal inflammation in patients with early NEC.

Time of Onset of Necrotizing Enterocolitis and Focal Perforation in Preterm Infants: Impact on Clinical, Surgical, and Histological Features

Objective: There is no gold standard test for diagnosis of necrotizing enterocolitis (NEC). Timing of onset is used in some definitions and studies in an attempt to separate NEC from focal intestinal perforation (FIP) with 14 days used as a cutoff. In a large, detailed data set we aimed to compare NEC and FIP in preterm infants born <32 weeks gestation, presenting before 14 days of life in comparison to cases presenting later. Design: Infants with NEC or FIP when parents had consented to enrollment in an observational and sample collection study were included from 2009 to 2019. Clinical, surgical, histological, and outcome data were extracted and reviewed by each author independently. Patients/Episodes: In 785 infants, 174 episodes of NEC or FIP were identified of which 73 (42%) occurred before 14 days, including 54 laparotomies and 19 episodes of medically managed NEC ("early"). There were 56 laparotomies and 45 episodes of medically managed NEC presenting on or after 14 days age ("late"). Results: In early cases, 41% of laparotomies were for NEC (22 cases) and 59% for FIP (32 cases), and in late cases, 91% of laparotomies (51 cases) were for NEC and 9% (five cases) were for FIP. NEC presenting early was more likely to present with an initial septic presentation rather than discrete abdominal pathology and less likely to have clear pneumatosis. Early cases did not otherwise differ clinically, surgically, or histologically or in outcomes compared with later cases. FIP features did not differ by age at presentation. Conclusions: Although most FIP occurred early, 14% occurred later, whereas almost one third (29%) of NEC cases (surgical and medical) presented early. Infant demographics and surgical and histological findings of early- and late-presenting disease did not differ, suggesting that early and late cases are not necessarily different subtypes of the same disease although a common pathway of different pathogenesis cannot be excluded. Timing of onset does not accurately distinguish NEC from FIP, and caution should be exercised in including timing of onset in diagnostic criteria.

Targeted inhibition of thrombin attenuates murine neonatal necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is an inflammatory bowel necrosis of premature infants and an orphan disease with no specific treatment. Most patients with confirmed NEC develop moderate-severe thrombocytopenia requiring one or more platelet transfusions. Here we used our neonatal murine model of NEC-related thrombocytopenia to investigate mechanisms of platelet depletion associated with this disease [K. Namachivayam, K. MohanKumar, L. Garg, B. A. Torres, A. Maheshwari, Pediatr. Res. 81, 817-824 (2017)]. In this model, enteral administration of immunogen trinitrobenzene sulfonate (TNBS) in 10-d-old mouse pups produces an acute necrotizing ileocolitis resembling human NEC within 24 h, and these mice developed thrombocytopenia at 12 to 15 h. We hypothesized that platelet activation and depletion occur during intestinal injury following exposure to bacterial products translocated across the damaged mucosa. Surprisingly, platelet activation began in our model 3 h after TNBS administration, antedating mucosal injury or endotoxinemia. Platelet activation was triggered by thrombin, which, in turn, was activated by tissue factor released from intestinal macrophages. Compared to adults, neonatal platelets showed enhanced sensitivity to thrombin due to higher expression of several downstream signaling mediators and the deficiency of endogenous thrombin antagonists. The expression of tissue factor in intestinal macrophages was also unique to the neonate. Targeted inhibition of thrombin by a nanomedicine-based approach was protective without increasing interstitial hemorrhages in the inflamed bowel or other organs. In support of these data, we detected increased circulating tissue factor and thrombin-antithrombin complexes in patients with NEC. Our findings show that platelet activation is an important pathophysiological event and a potential therapeutic target in NEC.

A Prospective Cohort Study of Fecal miR-223 and miR-451a as Noninvasive and Specific Biomarkers for Diagnosis of Necrotizing Enterocolitis in Preterm Infants

OBJECTIVE

The objective of this study is to evaluate the usefulness of fecal microRNA (miR)-223 and miR-451a, as novel noninvasive biomarkers for early diagnosis of necrotizing enterocolitis (NEC) in preterm infants.

METHODS

Among the top-listed target miRNAs in our previous differential microarray analysis, miR-223 and miR-451a were quantified in a pilot validation case-controlled study (NEC vs. non-NEC/nonsepsis infants; n = 6 in each group). A definitive prospective cohort study (n = 218) further assessed their clinical usefulness as noninvasive and specific diagnostic biomarkers. Fecal calprotectin was quantified in parallel for comparison.

RESULTS

Of 43 proven NEC cases in the cohort study, 24 (55.8%) had fecal samples recovered within the first 3 days of clinical presentation. Fecal miRNA-223 (10.5 fold), miR-451a (4.5 fold), and calprotectin (2.1 fold) concentrations were significant higher in NEC compared with the non-NEC group (p < 0.009). Accepting a minimum sensitivity of 0.75, the positive predictive values (PPVs) ranged between 0.19 and 0.20. Combining fecal biomarkers and CRP (Day 1) could marginally increase the PPVs (0.31-0.34) but adversely lowered the sensitivity (0.54-0.63).

CONCLUSIONS

Although fecal miRNA biomarkers and calprotectin concentrations were significantly higher in the NEC group, the considerable overlapping of concentrations between groups and low recovery of stool specimens within 72 h of clinical presentation rendered fecal noninvasive tests of limited clinical value in guiding diagnosis of NEC during the acute phase. A further study is underway to evaluate their roles in surveillance for predicting high-risk premature infants developing NEC.

Necrotizing enterocolitis: It's not all in the gut

Necrotizing enterocolitis is the leading cause of death due to gastrointestinal disease in preterm neonates, affecting 5–12% of neonates born at a very-low birth weight. Necrotizing enterocolitis can present with a slow and insidious onset, with some neonates displaying early symptoms such as feeding intolerance. Treatment during the early stages includes bowel rest and careful use of antibiotics, but surgery is required if pneumoperitoneum and intestinal perforation occur. Mortality rates among neonates requiring surgery are estimated to be 20–30%, mandating the development of non-invasive and reliable biomarkers to predict necrotizing enterocolitis before the onset of clinical signs. Such biomarkers would allow at-risk neonates to receive maximal preventative therapies such as careful nutritional consideration, probiotics, and increased skin-to-skin care.

Impact statement

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease; its high mortality rate mandates the development of non-invasive biomarkers to predict NEC before its onset. This review summarizes the pathogenesis, prevention, unresolved issues, and long-term outcomes of NEC.

The future of probiotics in the preterm infant

Probiotic administration to preterm infants is not universal despite randomised trial data from >10,000 infants, significant observational data and multiple meta-analyses. Advocates point to reductions in necrotising enterocolitis and sepsis, 'sceptics' hold concerns over data quality/interpretation or risks. Issues revolve around different products, primary outcomes, uncertain dosing strategies and individual large 'negative' trials alongside probiotic associated sepsis and quality control concerns. We review concerns and how to move probiotic use forward. Surprisingly little is known about parental perspectives, vital to inform next steps. How to share information and decisions around probiotic use now, and how this impacts on future available strategies is discussed. We address placebo controlled trials and propose alternate designs, including head to head studies, using 'routine' data collection systems, opt out consents and 'learning technologies' embedded in health care systems. We also raise the importance of underpinning mechanistic work to inform future trials.

A pilot case-control study of urine metabolomics in preterm neonates with necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a leading cause of gastrointestinal morbidity and mortality in preterm neonates. The aim of this pilot study was to explore using metabolomics alternations in the urine metabolites related to NEC that could possibly serve as diagnostic biomarkers of the disease. Urine samples were prospectively collected at the day of initial evaluation for NEC from 15 diseased preterm neonates (five Bell's stage I and ten stage II/III) and an equal number of matched controls. Urine metabolic profiles were assessed using non-targeted nuclear magnetic resonance spectroscopy and targeted liquid chromatography-tandem mass spectrometry monitoring 108 metabolites. Multivariate statistical models with data from either analytical approach showed clear separation between the metabolic profiles of neonates with NEC and controls. Twenty-five discriminant metabolites were identified belonging to amino and organic acids, sugars and vitamins. A number of metabolite combinations were found to have an excellent diagnostic performance in detecting neonates developing NEC. Our results show that the metabolic profile of neonates with NEC differs significantly from that of controls, making possible their separation using urine metabolomic analysis. Nevertheless, whether the small set of significant metabolites detected in this investigation could be used as early diagnostic biomarkers of NEC should be validated in larger studies.

Challenges in Advancing Necrotizing Enterocolitis Research

Progressing necrotizing enterocolitis research is difficult because the disease is variable in presentation, there are difficulties in making a precise diagnosis, a reliable agreed case-definition is currently lacking, and there is a paucity of preclinical research to identify etiologic targets. The major challenges of the cost of clinical trials and need for long-term outcome ascertainment could be eased through incorporation of novel randomization approaches and data collection into routine care, and collaboration between public-sector and industry funders.

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.

Plasma miR-1290 Is a Novel and Specific Biomarker for Early Diagnosis of Necrotizing Enterocolitis-Biomarker Discovery with Prospective Cohort Evaluation

OBJECTIVE

To discover specific circulating microRNA (miRNA) biomarkers for the early differentiation of necrotizing enterocolitis (NEC) from neonatal sepsis and inflammatory conditions.

STUDY DESIGN

The study comprised 3 distinct phases: differential microarray analysis to compare plasma miRNA expression profiles of NEC vs sepsis and non-NEC/nonsepsis cases, a case-control study to quantify dysregulated miRNAs as potential specific biomarkers of NEC, and a prospective cohort study to assess the diagnostic usefulness of the best miRNA biomarker(s).

RESULTS

A distinct miRNA expression profile was observed in the NEC compared with the sepsis and non-NEC/nonsepsis groups. miR-1290, miR-1246, and miR-375 were discovered to be specific biomarkers of NEC in the case-control study. In the cohort study (n = 301), plasma miR-1290 (day 0; >220 copies/µL) provided the greatest diagnostic usefulness for identifying both mild medical and severe surgical NEC cases. Of 20 infants with miR-1290 >650 copies/µL, 15 were diagnosed with NEC. Incorporating C-reactive protein (day 1; >15.8 mg/L) for cases with intermediate levels (220-650 copies/µL) in a 2-stage algorithm further optimized the diagnostic profile with a sensitivity of 0.83, a specificity of 0.96, a positive predictive value of 0.75, and a negative predictive value of 0.98. Importantly, 7 of 36 infants with NEC (19.4%) could be diagnosed 7.8-32.2 hours earlier (median, 13.3 hours) using miR-1290.

CONCLUSIONS

Plasma miR-1290 is a novel and specific biomarker that can effectively differentiate NEC cases from neonatal sepsis. miR-1290 facilitates neonatologists to confidently and timely reach a decision for early transfer of sick infants with NEC from community-based hospitals to tertiary surgical centers.

Understanding and Improving Diagnostic Tests: The Clinician Perspective

Recent advances in molecular and mass screening technologies have paved the way for discovery of novel diagnostic tests and/or biomarkers for accurate identification of specific diseases and organ injuries. However, new diagnostic tests/biomarkers should be subjected to thorough evaluation before introduction into routine clinical practice. This review focuses on the up-to-date methodology in designing and evaluating diagnostic tests/biomarkers, and assessing their clinical utilities for improving health care efficiency, cost-effectiveness and outcomes. In addition to improved diagnostic utilities, future diagnostic tests should be developed in collaboration with our industrial partners and be applicable at the bedside for disease surveillance.

An update on biomarkers of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) remains a devastating surgical emergency with high morbidity and mortality in preterm infants. Slow but steady progress has been made in past years searching for novel biomarkers of NEC, for both surveillance and diagnostic purposes. This review primarily focuses on recent discoveries: clinical applications of different categories of biomarkers for surveillance, early diagnosis, and predicting severity and prognosis; and understanding of pathophysiological mechanisms as a basis to rationalize the search for 'gut-associated specific biomarkers' of NEC. An important next step is to collaborate with our industrial partners to develop point-of-care tests, and to discover novel and gut-associated specific biomarkers that can be used for surveillance and early diagnosis of NEC in routine clinical settings.

Evolving understanding of neonatal necrotizing enterocolitis

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

The Potentials and Caveats of Mesenchymal Stromal Cell-Based Therapies in the Preterm Infant

Preponderance of proinflammatory signals is a characteristic feature of all acute and resulting long-term morbidities of the preterm infant. The proinflammatory actions are best characterized for bronchopulmonary dysplasia (BPD) which is the chronic lung disease of the preterm infant with lifelong restrictions of pulmonary function and severe consequences for psychomotor development and quality of life. Besides BPD, the immature brain, eye, and gut are also exposed to inflammatory injuries provoked by infection, mechanical ventilation, and oxygen toxicity. Despite the tremendous progress in the understanding of disease pathologies, therapeutic interventions with proven efficiency remain restricted to a few drug therapies with restricted therapeutic benefit, partially considerable side effects, and missing option of applicability to the inflamed brain. The therapeutic potential of mesenchymal stromal cells (MSCs)—also known as mesenchymal stem cells—has attracted much attention during the recent years due to their anti-inflammatory activities and their secretion of growth and development-promoting factors. Based on a molecular understanding, this review summarizes the positive actions of exogenous umbilical cord-derived MSCs on the immature lung and brain and the therapeutic potential of reprogramming resident MSCs. The pathomechanistic understanding of MSC actions from the animal model is complemented by the promising results from the first phase I clinical trials testing allogenic MSC transplantation from umbilical cord blood. Despite all the enthusiasm towards this new therapeutic option, the caveats and outstanding issues have to be critically evaluated before a broad introduction of MSC-based therapies.

Pathogenesis of NEC: Impact of an altered intestinal microbiome

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

Acylcarnitine Profiles Reflect Metabolic Vulnerability for Necrotizing Enterocolitis in Newborns Born Premature

OBJECTIVE

To evaluate the association between newborn acylcarnitine profiles and the subsequent development of necrotizing enterocolitis (NEC) with the use of routinely collected newborn screening data in infants born preterm.

STUDY DESIGN

A retrospective cohort study was conducted with the use of discharge records for infants born preterm admitted to neonatal intensive care units in California from 2005 to 2009 who had linked state newborn screening results. A model-development cohort of 94 110 preterm births from 2005 to 2008 was used to develop a risk-stratification model that was then applied to a validation cohort of 22 992 births from 2009.

RESULTS

Fourteen acylcarnitine levels and acylcarnitine ratios were associated with increased risk of developing NEC. Each log unit increase in C5 and free carnitine /(C16 + 18:1) was associated with a 78% and a 76% increased risk for developing NEC, respectively (OR 1.78, 95% CI 1.53-2.02, and OR 1.76, 95% CI 1.51-2.06). Six acylcarnitine levels, along with birth weight and total parenteral nutrition, identified 89.8% of newborns with NEC in the model-development cohort (area under the curve 0.898, 95% CI 0.889-0.907) and 90.8% of the newborns with NEC in the validation cohort (area under the curve 0.908, 95% CI 0.901-0.930).

CONCLUSIONS

Abnormal fatty acid metabolism was associated with prematurity and the development of NEC. Metabolic profiling through newborn screening may serve as an objective biologic surrogate of risk for the development of disease and thus facilitate disease-prevention strategies.

Biomarkers for the diagnosis of neonatal sepsis and necrotizing enterocolitis: Clinical practice guidelines

Sepsis and necrotizing enterocolitis are major contributors to morbidity and mortality in neonates, especially in those born preterm. While therapeutic interventions are available for both (for e.g. antibiotics), a major dilemma is early diagnosis so that these interventions can be done in a timely manner. As clinical evaluation alone is unreliable in identifying infants in the early stages of neonatal sepsis or necrotizing enterocolitis, there is a need to find specific biomarkers associated with these conditions to improve diagnostic capabilities. Optimal use of biomarkers in the identification and management of affected neonates requires an understanding of the properties of each marker within the timeline of the inflammatory response. We propose that early- and mid-phase markers such as neutrophil CD64 and procalcitonin should be combined with the late-phase biomarker C-reactive protein for maximal diagnostic benefit. Appropriately powered trials evaluating the serial measurements of these markers in decisions related to antibiotic stewardship in the neonatal population are indicated, in addition to more studies investigating other potentially useful biomarkers.

Association between the p.Thr1406Asn polymorphism of the carbamoyl-phosphate synthetase 1 gene and necrotizing enterocolitis: A prospective multicenter study

The p.Thr1406Asn (rs1047891) polymorphism of the carbamoyl-phosphate synthetase 1 (CPS1) gene has been linked to functional consequences affecting the downstream availability of the nitric oxide precursor L-arginine. L-arginine concentrations are decreased in preterm infants with necrotizing enterocolitis (NEC). In this multicenter prospective study, we investigated the association of the p.Thr1406Asn polymorphism with NEC in 477 preterm infants (36 cases of NEC) from 4 European neonatal intensive care units (Maastricht, Las Palmas de Gran Canaria, Mantova, and Milan). Allele and genotype frequencies of the p.Thr1406Asn polymorphism did not significantly differ between the infants with and without NEC. In contrast, the minor A-allele was significantly less frequent in the group of 64 infants with the combined outcome NEC or death before 34 weeks of corrected gestational age than in the infants without the outcome (0.20 vs. 0.31, P = 0.03). In addition, a significant negative association of the A-allele with the combined outcome NEC or death was found using the dominant (adjusted odds ratio, aOR: 0.54, 95% CI 0.29–0.99) and the additive (aOR 0.58, 95% CI 0.36–0.93) genetic models. In conclusion, our study provides further evidence that a functional variant of the CPS1 gene may contribute to NEC susceptibility.

Necrotizing enterocolitis: new insights into pathogenesis and mechanisms

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

Plasma D-lactate Levels in Necrotizing Enterocolitis in Premature Infants

Background

D-Lactate is normally present in the blood of humans at nanomolar concentrations due to methylglyoxal metabolism; millimolar D-lactate concentrations can arise due to excess gastrointestinal microbial production.

Objectives

To examine the levels of plasma D-lactate in the necrotizing enterocolitis in premature infants.

Patients and Methods

128 premature infants were divided into control (group I, n = 69), feeding intolerance (group II, n = 42) and NEC (group III, n = 27) groups. Plasma D-lactate levels were measured at the onset of feeding intolerance or NEC and at weeks 2-3 in control infants (group I) by ELISA. Data were analyzed using descriptive statistics, non-parametric tests and Student’s t-test.

Results

In groups I, II, III, median birth weights were 1845.7 ± 267.5 g, 1913.1 ± 306.5 g, and 1898.4 ± 285.3 g, median gestational ages were 34.3 ± 1.7 weeks, 33.9 ± 2.2 weeks and 35.1 ± 2.6 weeks, ages of sampling were 12.3 ± 2.9 days, 14.6 ± 3.7 days and 15.1 ± 1.8 days, respectively. The differences of median birth weights, median gestational ages and ages of sampling were not statistically significant (P > 0.05). The plasma D-lactate levels in groups I, II, III were 3.6 ± 1.9 μg/mL, 12.7 ± 8.3 μg/mL, and 35.4 ± 29.1 μg/mL, respectively, group III had higher plasma D-lactate level than groups I, II, and the difference among these groups was significant (x² = 21.6, P < 0.01).

Conclusions

Plasma D-lactate significantly increased early in NEC. Plasma D-lactate levels were associated with extensive disease in NEC infants. Therefore, it could be used as a diagnosis indicator in the early stage of NEC.

Evaluation of the expression of I-FABP and L-FABP in a necrotizing enterocolitis model after the use of Lactobacillus acidophilus

BACKGROUND/PURPOSE

Necrotizing enterocolitis (NEC) is a severe intestinal disease that primarily affects premature babies, leading to high mortality and morbidity. Probiotics represent an important alternative prophylaxis for NEC but its mechanism of action is poorly understood. Moreover, intestinal and liver-type fatty acid-binding proteins (I-FABP and L-FABP) may be utilized because markers of intestinal injury, including NEC. We aimed to evaluate the protection induced by the Lactobacillus acidophilus on the intestines of newborn rats submitted to experimental NEC using I-FABP and L-FABP as biomarkers.

METHODS

Sprague-Dawley newborn rats were divided into three groups: (1) C (control)-breast-fed; (2) NEC-subjected to NEC protocol and (3) NECP-NEC+probiotic. Morphometric, intestinal lesion, immunohistochemistry and Western blotting analysis were performed. Statistical significant differences were considered when p<0.05.

RESULTS

Intestinal weight was lower in NEC and NECP compared to C (p<0.05). Intestinal injury was lower in NECP compared to NEC. Prophylactic probiotic recovered mucosa and muscular layers' thickness to C levels (p<0.05). I-FABP and L-FABP expressions in NECP showed intermediate values between C and NEC.

CONCLUSION

L. acidophilus had a protective effect on the development of NEC and FABPs could demonstrate the degree of tissular damage of the intestine.

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.