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

Research Gaps in Pediatric Heart Failure: Defining the Gaps and Then Closing Them Over the Next Decade

Given the numerous opportunities and the wide knowledge gaps in pediatric heart failure, an international group of pediatric heart failure experts with diverse backgrounds were invited and tasked with identifying research gaps in each pediatric heart failure domain that scientists and funding agencies need to focus on over the next decade.

Regulation of Natural Killer Cell TGF-β and AhR Signaling Pathways Via the Intestinal Microbiota is Critical for Host Defense Against Alcohol-Associated Bacterial Pneumonia

Alcohol use is an independent risk factor for the development of bacterial pneumonia due, in part, to impaired mucus-facilitated clearance, macrophage phagocytosis, and recruitment of neutrophils. Alcohol consumption is also known to reduce peripheral natural killer (NK) cell numbers and compromises NK cell cytolytic activity, especially NK cells with a mature phenotype. However, the role of innate lymphocytes, such as NK cells during host defense against alcohol-associated bacterial pneumonia is essentially unknown. We have previously shown that indole supplementation mitigates increases in pulmonary bacterial burden and improves pulmonary NK cell recruitment in alcohol-fed mice, which were dependent of aryl hydrocarbon receptor (AhR) signaling. Employing a binge-on-chronic alcohol-feeding model we sought to define the role and interaction of indole and NK cells during pulmonary host defense against alcohol-associated pneumonia. We demonstrate that alcohol dysregulates NK cell effector function and pulmonary recruitment via alterations in two key signaling pathways. We found that alcohol increases transforming growth factor beta (TGF-β) signaling, while suppressing AhR signaling. We further demonstrated that NK cells isolated from alcohol-fed mice have a reduced ability to kill Klebsiella pneumoniae. NK cell migratory capacity to chemokines was also significantly altered by alcohol, as NK cells isolated from alcohol-fed mice exhibited preferential migration in response to CXCR3 chemokines but exhibited reduced migration in response to CCR2, CXCR4, and CX3CR1 chemokines. Together this data suggests that alcohol disrupts NK cell specific TGF-β and AhR signaling pathways leading to decreased pulmonary recruitment and cytolytic activity thereby increasing susceptibility to alcohol-associated bacterial pneumonia.

Putative intestinal permeability markers do not correlate with cardiometabolic health and gut microbiota in humans, except for peptides recognized by a widely used zonulin ELISA kit

BACKGROUND AND AIMS

Cardiometabolic diseases refer to a group of interrelated conditions, sharing metabolic dysfunctions like insulin resistance, obesity, dyslipidemia, and hypertension. The gut microbiota has been associated with CMD and related conditions. Alterations in the intestinal epithelium permeability triggered by chronic stress and diet could bridge gut microbiota with inflammation and CMD development. Here, we assessed the relationship between intestinal permeability and circulating SCFAs with cardiometabolic health status (CMHS) and gut microbiota in a sample of 116 Colombian adults.

METHODS AND RESULTS

Plasma levels of lipopolysaccharide-binding protein (LBP), intestinal fatty acid-binding protein (I-FABP), claudin-3, and purported zonulin peptides (PZP) were measured by ELISA, whereas plasmatic levels of acetate, propionate, butyrate, isobutyrate, and valerate were measured by gas chromatography/mass spectrometry. In addition, for further statistical analysis, we took data previously published by us on this cohort, including gut microbiota and multiple CMD risk factors that served to categorize subjects as cardiometabolically healthy or cardiometabolically abnormal. From univariate and multivariate statistical analyses, we found the levels of I-FABP, LBP, and PZP increased in the plasma of cardiometabolically abnormal individuals, although only PZP reached statistical significance.

CONCLUSIONS

Our results did not confirm the applicability of I-FABP, LBP, claudin-3, or SCFAs as biomarkers for associating intestinal permeability with the cardiometabolic health status in these subjects. On the other hand, the poorly characterized peptides detected with the ELISA kit branded as "zonulin" were inversely associated with cardiometabolic dysfunctions and gut microbiota. Further studies to confirm the true identity of these peptides are warranted.

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.

Dynamic Changes in Colonic Structure and Protein Expression Suggest Regulatory Mechanisms of Colonic Barrier Function in Torpor-Arousal Cycles of the Daurian Ground Squirrel

Background: Both pathological conditions and hibernation can affect the barrier function of small intestine mucosa. However, the effect of hibernation on the barrier function of colonic mucosa remains unclear. Methods: We investigated morphological changes in colonic mucosa, the concentrations of specific proteins and molecules, and the enzymatic activity of diamine oxidase (DAO), in serum and colonic tissue; the expression of tight junction proteins and mucin, and the changes in inflammatory, farnesoid X receptor (FXR)–small heterodimer partner (SHP), and apoptosis-related molecules that could play a role in gut permeability changes in Daurian ground squirrels in summer active (SA), late torpor (LT), and interbout arousal (IBA) periods. Results: The results show that hibernation reduced the thickness of the colonic mucosa and the depth of the crypt, decreased the number of goblet cells (GCs), and damaged the structure of some microvilli. The concentrations of proteins and molecules, and the enzymatic activity of DAO, were all increased in the serum and colon, and the localization of tight junction proteins and mucin in the colonic mucosa were altered (compensatory response). Although the ground squirrels ate during the interbout arousal period, the changes remained similar to the response to torpor. Inflammation, apoptosis–anti-apoptosis, and FXR–SHP signaling may be involved in the possible changes in intestinal gut permeability during the torpor–arousal cycle in Daurian ground squirrels. In addition, periodic interbout arousal may play an inflammation-correcting role during the long hibernation season of Daurian ground squirrels.

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.

Emerging Biomarkers for Screening and Management of Celiac Disease

Celiac disease (CeD) is a chronic, immune-mediated enteropathy that is precipitated by dietary gluten in genetically predisposed individuals expressing HLA-DQ2 and/or HLA-DQ8. In the current clinical practice, there are many serologic studies to aid in the diagnosis of CeD which include autoantibodies like IgA antitissue transglutaminase, antiendomysium, and antideamidated forms of gliadin peptide antibodies. Small intestinal biopsy has long been considered an essential step for the diagnosis of CeD. However, in the recent era, researchers have explored the possibility of CeD screening and diagnosis without endoscopy or biopsy. The newer emerging biomarkers of CeD appear promising in diagnostic evaluation and subsequent monitoring of disease. In this review of literature, we have explored the emerging biomarker-based diagnostic evaluation and monitoring of CeD.

Intestinal fatty acid binding protein is a disease biomarker in paediatric coeliac disease and Crohn's disease

Background

There is a clinical need to develop biomarkers of small bowel damage in coeliac disease and Crohn’s disease. This study evaluated intestinal fatty acid binding protein (iFABP), a potential biomarker of small bowel damage, in children with coeliac disease and Crohn’s disease.

Methods

The concentration iFABP was measured in plasma and urine of children with ulcerative colitis, coeliac disease, and Crohn’s disease at diagnosis and from the latter two groups after treatment with gluten free diet (GFD) or exclusive enteral nutrition (EEN), respectively. Healthy children (Controls) were also recruited.

Results

138 children were recruited. Plasma but not urinary iFABP was higher in patients with newly diagnosed coeliac disease than Controls (median [Q1, Q3] coeliac disease: 2104 pg/mL 1493, 2457] vs Controls: 938 pg/mL [616, 1140], p = 0.001). Plasma or urinary iFABP did not differ between patients with coeliac on GFD and Controls. Baseline iFABP in plasma decreased by 6 months on GFD (6mo GFD: 1238 pg/mL [952, 1618], p = 0.045). By 12 months this effect was lost, at which point 25% of patients with coeliac disease had detectable gluten in faeces, whilst tissue transglutaminase IgA antibodies (TGA) continued to decrease. At diagnosis, patients with Crohn’s disease had higher plasma iFABP levels than Controls (EEN Start: 1339 pg/mL [895, 1969] vs Controls: 938 pg/mL [616, 1140], p = 0.008). iFABP did not differ according to Crohn’s disease phenotype. Induction treatment with EEN tended to decrease (p = 0.072) iFABP in plasma which was no longer different to Controls (EEN End: 1114 pg/mL [689, 1400] vs Controls: 938 pg/mL [616, 1140], p = 0.164). Plasma or urinary iFABP did not differ in patients with ulcerative colitis from Controls (plasma iFABP, ulcerative colitis: 1309 pg/mL [1005, 1458] vs Controls: 938 pg/mL [616, 1140], p = 0.301; urinary iFABP ulcerative colitis: 38 pg/mg [29, 81] vs Controls: 53 pg/mg [27, 109], p = 0.605).

Conclusions

Plasma, but not urinary iFABP is a candidate biomarker with better fidelity in monitoring compliance during GFD than TGA. The role of plasma iFABP in Crohn’s disease is promising but warrants further investigation.

Trial registration: Clinical Trials.gov, NCT02341248. Registered on 19/01/2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02334-6.

Association of neutrophil to lymphocyte ratio with preterm necrotizing enterocolitis: a retrospective case-control study

Background

There have been few studies on the relationship between the neutrophil to lymphocyte ratio (NLR) and necrotizing enterocolitis (NEC). We conducted a retrospective case-control study to investigate this relationship in preterm neonates.

Methods

A total of 199 preterm neonates diagnosed with NEC between January 2018 and January 2020 were included in this study. For each preterm infant with NEC that was admitted to the neonatal intensive care unit (NICU), controls were preterm neonates (matched for gestation and year of birth) who were not diagnosed with NEC. Exclusion criteria were post-maturity, small or large for gestational age (week of pregnancy), congenital major anomalies, and cyanotic congenital heart disease. Univariate and multivariate logistic regression analyses were used to identify the association between NLR and preterm NEC.

Results

This study included 93 preterm neonates with NEC and 106 matched controls. There were no significant differences in gestational age (GA), birth weight (BW), age, sex, vaginal delivery (VD), chorioamnionitis (CA), and gestational diabetes mellitus (GDM) between the groups. Compared with the control group, the lower and higher NLR levels in the NEC group were statistically different. Following univariate analysis, NLR was a risk factor for NEC (odds ratio [OR], 1.40; 95% confidence interval [CI], 1.00–1.90; P = 0.042), and according to multivariate analysis, risk factors for NEC were NLR ≥ 3.20 and NLR < 1.60, within 1 week before NEC diagnosis. Thus, NLR values of ≥ 1.60 and < 3.20 were determined as the predictive cut-off values for protecting preterm infants from NEC (Model I: OR, 0.20; 95% CI, 0.10–0.40; P < 0.001) and (Model II: OR, 0.10; 95% CI, 0.00–0.40; P < 0.001].

Conclusions

NLR ≥ 1.60 and NLR < 3.20 were associated with a decreased risk of NEC in 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.

The short-term effects of RBC transfusions on intestinal injury in preterm infants

BACKGROUND

Anemic preterm infants may require red blood cell (RBC) transfusions to maintain sufficient oxygen supply to vital organs. Transfusion treatment, however, may have adverse intestinal effects. We aimed to investigate the short-term effects of RBC transfusions, hypothesizing to find signs of oxidative stress and intestinal injury, possibly related to levels of splanchnic (re-)oxygenation.

METHODS

We prospectively included preterm infants (gestational age < 32 weeks). We measured urinary biomarkers for oxidative stress (8-isoprostane) and intestinal cell injury (intestinal fatty acid-binding protein, I-FABP) shortly before and after RBC transfusion. Splanchnic oxygen saturation (r_sSO₂) and r_sSO₂ variability were assessed simultaneously.

RESULTS

Twenty-nine preterm infants received 58 RBC transfusions at various postnatal ages. Six of them developed necrotizing enterocolitis (NEC) after transfusion. Urinary 8-isoprostane and I-FABP increased following RBC transfusion (median 282-606 pg/ml and 4732-6968 pg/ml, p < 0.01), more pronounced in infants who developed NEC. Change in I-FABP correlated with change in 8-isoprostane (rho = 0.623, p < 0.01). Lower r_sSO₂ variability, but not higher mean r_sSO₂ was associated with higher 8-isoprostane and I-FABP levels after transfusion.

CONCLUSIONS

Preterm RBC transfusions are associated with concomitant signs of oxidative stress and intestinal injury, parallel with lower variability in splanchnic oxygenation. This may represent the early pathogenetic process of transfusion-associated NEC.

IMPACT

Red blood cell (RBC) transfusions in preterm infants are associated with a near 2-fold increase in urinary biomarkers for oxidative stress (8-isoprostane) and intestinal cell injury (intestinal fatty acid-binding protein, I-FABP). Magnitude of change in I-FABP strongly correlated with the magnitude of 8-isoprostane change, suggesting a role for oxidative stress in the pathogenesis of intestinal injury. Lower splanchnic oxygen saturation variability following RBC transfusion was associated with higher 8-isoprostane and I-FABP levels. Loss of splanchnic variability after RBC transfusion may result from increased oxidative stress and its concomitant intestinal injury, possibly representing the early pathogenetic process of transfusion-associated necrotizing enterocolitis.

ZIP8-Mediated Intestinal Dysbiosis Impairs Pulmonary Host Defense against Bacterial Pneumonia

Pneumococcal pneumonia is a leading cause of morbidity and mortality worldwide. An increased susceptibility is due, in part, to compromised immune function. Zinc is required for proper immune function, and an insufficient dietary intake increases the risk of pneumonia. Our group was the first to reveal that the Zn transporter, ZIP8, is required for host defense. Furthermore, the gut microbiota that is essential for lung immunity is adversely impacted by a commonly occurring defective ZIP8 allele in humans. Taken together, we hypothesized that loss of the ZIP8 function would lead to intestinal dysbiosis and impaired host defense against pneumonia. To test this, we utilized a novel myeloid-specific Zip8KO mouse model in our studies. The comparison of the cecal microbial composition of wild-type and Zip8KO mice revealed significant differences in microbial community structure. Most strikingly, upon a S. pneumoniae lung infection, mice recolonized with Zip8KO-derived microbiota exhibited an increase in weight loss, bacterial dissemination, and lung inflammation compared to mice recolonized with WT microbiota. For the first time, we reveal the critical role of myeloid-specific ZIP8 on the maintenance of the gut microbiome structure, and that loss of ZIP8 leads to intestinal dysbiosis and impaired host defense in the lung. Given the high incidence of dietary Zn deficiency and the ZIP8 variant allele in the human population, additional investigation is warranted to improve surveillance and treatment strategies.

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.

Neonatal anemia relates to intestinal injury in preterm infants

BACKGROUND

Anemia is associated with decreased tissue oxygenation in preterm infants and may contribute to developing necrotizing enterocolitis (NEC). We aimed to investigate whether hemoglobin level is associated with intestinal injury, by comparing anemic infants 10 days prior to red blood cell (RBC) transfusion with non-anemic controls.

METHODS

A nested case-control study in which we matched anemic preterms (gestational age (GA) < 32 weeks) with non-anemic controls (1:1), based on GA, birth weight (BW), and postnatal age. We measured urinary intestinal fatty acid-binding protein, I-FABP, marker for intestinal injury, twice weekly. Simultaneously, we assessed splanchnic oxygen saturation (r_sSO₂) and r_sSO₂ variability.

RESULTS

Thirty-six cases and 36 controls were included (median GA 27.6 weeks, BW 1020 grams). Median I-FABP level was higher in cases from 6 days to 24-h before transfusion (median ranging: 4749-8064 pg/ml versus 2194-3751 pg/ml). R_sSO₂ and r_sSO₂ variability were lower in cases than controls shortly before transfusion. Hemoglobin levels correlated negatively with r_sSO₂ and r_sSO₂ variability in cases, and negatively with I-FABP in cases and controls together.

CONCLUSIONS

Urinary I-FABP levels were higher in anemic infants before RBC transfusion than in non-anemic matched controls, suggesting intestinal injury associated with anemia. This may predispose to NEC in some anemic preterm infants.

IMPACT

Anemia is a common comorbidity in preterm infants and may lead to impaired splanchnic oxygen saturation and intestinal tissue hypoxia, a proposed mechanism for NEC. Lower hemoglobin level is associated with higher urinary I-FABP levels, a marker for intestinal injury, both in anemic preterm infants and in cases and controls together. Lower splanchnic oxygen saturation and reduction of its variability are associated with higher urinary I-FABP levels in anemic preterm infants before their first RBC transfusion. These results support the hypothesis that anemia in very preterm infants results in intestinal cell injury, which may precede NEC development in some.

Association between glial fibrillary acidic protein, glial-derived neurotrophic factor, and fatty acid-binding protein-2 at birth in the incidence of necrotizing enterocolitis in preterm infants

BACKGROUND

This study aimed to analyze the relationship between glial fibrillary acidic protein (GFAP), glial-derived neurotrophic factor (GDNF), and fatty acid-binding protein-2 (FABP-2) in preterm infants on the incidence of NEC.

METHODS

Preterm infants with a birth weight <1,500 g and gestational age <34 weeks were included in this study. Biomarker examination was performed using the umbilical vein blood at birth (first sample). Biomarker examination was repeated if the infant developed symptoms of NEC using peripheral vein blood (second sample). Infants were observed for 14 days. If NEC did not exist, a biomarker examination was performed at 14 days.

RESULTS

This study included 30 preterm infants, nine infants experienced NEC. The values of GFAP, GDNF, and FABP-2 (median and range) in the group with NEC were higher than those in the group without NEC in both the first samples {GFAP [1.40 (0.20-6.50) vs. 0.30 (0.10-1.30) P = 0.014], GDNF [2.84 (1.05-14.11) vs. 1.56 (1.07-3.48) P = 0.050], and FABP-2 [621.70 (278.40-2,207.00) vs. 294.20 (211.40-597.50) P = 0.002]} and second samples {GFAP [2.40 (0.30-3.10) vs. 0.30 (0.10-0.60) P = 0.003], GDNF [2.99 (0.56-10.30) vs. 1.46 (0.85-2.24) P = 0.019], and FABP-2 [646.8 (179.20-1,571.00) vs. 314.90 (184.70-521.60) P = 0.040]}. In infants with NEC, the median values of GFAP [2.40 (0.30-3.10) vs. 1.40 (0.20-6.50) P = 0.767], GDNF [2.99 (0.56-10.30) vs. 2.84 (1.05-14.11) P = 0.859], and FABP-2 [646.80 (179.20-1,571.00) vs. 621.70 (278.40-2,207.00) P = 0.953] in the second sample were higher than those in the first sample. Logistic regression demonstrated that GFAP at birth (Odds Ratio [OR] = 15.629, 95% Confidence Interval [CI] = 1.697-143.906, P = 0.015) and FABP-2 levels at birth (OR = 1.008, 95% CI = 1.001-1.015, P = 0.033) were significantly associated with an increased risk of NEC.

CONCLUSION

Increased GFAP, GDNF, and FABP-2 at birth are associated with NEC occurrence within two weeks of birth. These findings suggest that early-onset NEC is associated with intestinal injury that occurs during the perinatal or even prenatal period.

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.

Pulmonary immune cell trafficking promotes host defense against alcohol-associated Klebsiella pneumonia

The intestinal microbiota generates many different metabolites which are critical for the regulation of host signaling pathways. In fact, a wide-range of diseases are associated with increased levels of local or systemic microbe-derived metabolites. In contrast, certain bacterial metabolites, such as tryptophan metabolites, are known to contribute to both local and systemic homeostasis. Chronic alcohol consumption is accompanied by alterations to intestinal microbial communities, and their functional capacities. However, little is known about the role of alcohol-associated dysbiosis on host defense against bacterial pneumonia. Our previous work using fecal transplantation demonstrated that alcohol-associated intestinal dysbiosis, independent of ethanol consumption, increased susceptibility to Klebsiella pneumonia. Here, we demonstrate that intestinal microbiota treatments mitigate the increased risk of alcohol-associated pneumonia. Treatment with the microbial metabolite indole or with probiotics reduced pulmonary and extrapulmonary bacterial burden, restored immune responses, and improved cellular trafficking required for host defense. Protective effects were, in part, mediated by aryl hydrocarbon receptors (AhR), as inhibition of AhR diminished the protective effects. Thus, alcohol appears to impair the production/processing of tryptophan catabolites resulting in immune dysregulation and impaired cellular trafficking. These data support microbiota therapeutics as novel strategies to mitigate the increased risk for alcohol-associated bacterial pneumonia.

Samuelson et al show that alcohol impairs the production/processing of microbial metabolites, specifically tryptophan catabolites, resulting in immune dysregulation and impaired cellular trafficking for optimal host defense. The metabolite, indole, or probiotics making indole metabolites mitigate alcohol-induced susceptibility to Klebsiella-associated pneumonia, and that the mechanisms are partially dependent on AhR.

Weight shapes the intestinal microbiome in preterm infants: results of a prospective observational study

BACKGROUND

The intestinal microbiome in preterm infants differs markedly from term infants. It is unclear whether the microbiome develops over time according to infant specific factors.

METHODS

We analysed (clinical) metadata - to identify the main factors influencing the microbiome composition development - and the first meconium and faecal samples til the 4th week via 16 S rRNA amplican sequencing.

RESULTS

We included 41 infants (gestational age 25-30 weeks; birth weight 430-990 g. Birth via Caesarean section (CS) was associated with placental insufficiency during pregnancy and lower BW. In meconium samples and in samples from weeks 2 and 3 the abundance of Escherichia and Bacteroides (maternal faecal representatives) were associated with vaginal delivery while Staphylococcus (skin microbiome representative) was associated with CS. Secondly, irrespective of the week of sampling or the mode of birth, a transition was observed as children children gradually increased in weight from a microbiome dominated by Staphylococcus (Bacilli) towards a microbiome dominated by Enterobacteriaceae (Gammaproteobacteria).

CONCLUSIONS

Our data show that the mode of delivery affects the meconium microbiome composition. They also suggest that the weight of the infant at the time of sampling is a better predictor for the stage of progression of the intestinal microbiome development/maturation than postconceptional age as it less confounded by various infant-specific factors.

Exfoliated epithelial cell transcriptome reflects both small and large intestinal cell signatures in piglets

Assessing intestinal development and host-microbe interactions in healthy human infants requires noninvasive approaches. We have shown that the transcriptome of exfoliated epithelial cells in feces can differentiate breast-fed and formula-fed infants and term and preterm infants. However, it is not fully understood which regions of the intestine that the exfoliated cells represent. Herein, the transcriptional profiles of exfoliated cells with that of the ileal and colonic mucosa were compared. We hypothesized that exfoliated cells in the distal colon would reflect mucosal signatures of more proximal regions of the gut. Two-day-old piglets (n = 8) were fed formulas for 20 days. Luminal contents and mucosa were collected from ileum (IL), ascending colon (AC), and descending (DC) colon, and mRNA was extracted and sequenced. On average, ∼13,000 genes were mapped in mucosal tissues and ∼10,000 in luminal contents. The intersection of detected genes between three mucosa regions and DC exfoliome indicated an approximately 99% overlap. On average, 49% of the genes in IL, AC, and DC mucosa were present in the AC and DC exfoliome. Genes expressed predominantly in specific anatomic sites (stomach, pancreas, small intestine, colon) were detectable in exfoliated cells. In addition, gene markers for all intestinal epithelial cell types were expressed in the exfoliome representing a diverse array of cell types arising from both the small and large intestine. Genes were mapped to nutrient absorption and transport and immune function. Thus, the exfoliome represents a robust reservoir of information in which to assess intestinal development and responses to dietary interventions.NEW & NOTEWORTHY The transcriptome of exfoliated epithelial cells in stool contain gene signatures from both small and large intestinal mucosa affording a noninvasive approach to assess gut health and function.

New Insights on End-Stage Renal Disease and Healthy Individual Gut Bacterial Translocation: Different Carbon Composition of Lipopolysaccharides and Different Impact on Monocyte Inflammatory Response

Chronic kidney disease induces disruption of the intestinal epithelial barrier, leading to gut bacterial translocation. Here, we appreciated bacterial translocation by analyzing circulating lipopolysaccharides (LPS) using two methods, one measuring only active free LPS, and the other quantifying total LPS as well as LPS lipid A carbon chain length. This was done in end-stage renal disease (ESRD) patients and healthy volunteers (HV). We observed both higher LPS concentration in healthy volunteers and significant differences in composition of translocated LPS based on lipid A carbon chain length. Lower LPS activity to mass ratio and higher concentration of high-density lipoproteins were found in HV, suggesting a better plasma capacity to neutralize LPS activity. Higher serum concentrations of soluble CD14 and pro-inflammatory cytokines in ESRD patients confirmed this hypothesis. To further explore whether chronic inflammation in ESRD patients could be more related to LPS composition rather than its quantity, we tested the effect of HV and patient sera on cytokine secretion in monocyte cultures. Sera with predominance of 14-carbon chain lipid A-LPS induced higher secretion of pro-inflammatory cytokines than those with predominance of 18-carbon chain lipid A-LPS. TLR4 or LPS antagonists decreased LPS-induced cytokine production by monocytes, demonstrating an LPS-specific effect. Thereby, septic inflammation observed in ESRD patients may be not related to higher bacterial translocation, but to reduced LPS neutralization capacity and differences in translocated LPS subtypes.

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.

Low serum albumin concentration predicts the need for surgical intervention in neonates with necrotizing enterocolitis

PURPOSE

To investigate whether serum albumin (SA) concentration can predict the need for surgical intervention in neonates with necrotizing enterocolitis (NEC).

METHODS

Retrospective review of all cases with NEC Bell's stage 2 and 3 that were treated in a single center between 2009 and 2015. Data on patient demographics, clinical parameters, laboratory findings and surgical status were recorded. Receiver operating characteristics analysis was used to evaluate optimal cutoffs and predictive values.

RESULTS

Overall, 151 neonates with NEC were identified. Of these, 132 (87.4%) had confirmed NEC Bell's stage 2. The median gestational age was 28.4 (range, 23.1-39.0) weeks and 69 (52.3%) had a birth weight of ≤1000 g. Sixty-eight (51.5%) underwent surgery, showing a sustained reduction in SA over time with significantly lower median SA levels compared to 64 (48.5%) cases that responded well to medical treatment (18.3 ± 3.7 g/L vs. 26.0 ± 2.0 g/L; P < 0.001). SA concentration of ≤20 g/L on day 2 of NEC diagnosis was a significant predictor for surgery (OR 3.41; P = 0.019) with a positive predictive value of 71.4%.

CONCLUSIONS

An SA concentration of ≤20 g/L on day 2 of the NEC disease process is associated with a higher likelihood for surgical intervention in neonates with NEC Bell's stage 2. SA, in combination with other clinical parameters and serological markers, may be a useful predictive tool for surgery in NEC.

LEVEL OF EVIDENCE

II.

The Intestinal Barrier and Current Techniques for the Assessment of Gut Permeability

The intestinal barrier is essential in human health and constitutes the interface between the outside and the internal milieu of the body. A functional intestinal barrier allows absorption of nutrients and fluids but simultaneously prevents harmful substances like toxins and bacteria from crossing the intestinal epithelium and reaching the body. An altered intestinal permeability, a sign of a perturbed barrier function, has during the last decade been associated with several chronic conditions, including diseases originating in the gastrointestinal tract but also diseases such as Alzheimer and Parkinson disease. This has led to an intensified interest from researchers with diverse backgrounds to perform functional studies of the intestinal barrier in different conditions. Intestinal permeability is defined as the passage of a solute through a simple membrane and can be measured by recording the passage of permeability markers over the epithelium via the paracellular or the transcellular route. The methodological tools to investigate the gut barrier function are rapidly expanding and new methodological approaches are being developed. Here we outline and discuss, in vivo, in vitro and ex vivo techniques and how these methods can be utilized for thorough investigation of the intestinal barrier.

Normative values for circulating intestinal fatty acid binding protein and calprotectin across gestational ages

Background

Necrotizing enterocolitis (NEC) is associated with significant morbidity and mortality. Serum biomarkers to aid diagnosis, such as intestinal fatty acid binding protein (IFABP) and calprotectin, are actively being investigated; however, the normative values of these markers among healthy premature and term infants remains unknown. We sought to identify normative values for the serum concentrations of IFABP and calprotectin across gestational (GA) and post-menstrual age.

Methods

We collected serum from infants (24–40 weeks GA) in the first week of life and at multiple time points in a sub-cohort of premature infants (24–29 weeks GA), excluding sepsis or known intestinal disease. IFABP and calprotectin were measured using ELISA. Groups were compared with descriptive statistics and mixed effects linear regression.

Results

One hundred twelve infants had specimens in the first week of life, and 19 premature infants had longitudinal specimens. IFABP concentration in the first week of life was low and did not differ across gestational ages. Longitudinally, IFABP increased 4% per day (P < 0.001). Calprotectin concentration in the first week of life was more variable. An inverse relationship between day of life and calprotectin level was found in the longitudinal cohort (P < 0.001).

Conclusions

Serum IFABP and calprotectin fluctuate over time. Infants had low levels of IFABP during the first week of life, independent of gestational age, and levels increased longitudinally in premature infants. Calprotectin levels generally declined over time. Normative data for infants is necessary to establish meaningful cut-off levels for clinical use.

Toll-like receptor distribution in colonic epithelium and lamina propria is disrupted in HIV viremic, immune success, and failure

DESIGN

Since intestinal immunity and the microbiome are disrupted in HIV disease, we studied the abundance of innate immune sensors, Toll-like receptors (TLRs), in the mucosa of participants with viremia, prior to antiretroviral therapy (ART), immune success (>500 CD4 T cells/μl after 2 years of ART; suppressed viremia), and immune failure (<350 CD4 T cells/μl after 2 years of ART; suppressed viremia). We hypothesized that disruption of intestinal TLR abundance and location provides a mechanism behind persistent inflammation.

METHODS

Immunofluorescence for TLR3, TLR4, and TLR9 on paraffin embedded biopsies from uninfected, viremic, immune success, and immune failure colons was imaged by deconvolution microscopy and quantified with MetaMorph software. Plasma levels of C-reactive protein, IL-6, and intestinal fatty-acid binding protein (I-FABP) were correlated with TLR expression.

RESULTS

Viremic participants have significantly higher levels of TLR3 and TLR9 on surface epithelium and in crypts when compared with uninfected controls. TLR3 is further elevated in immune failure and immune success. TLR9 abundance remains elevated in immune failure and is normalized in immune success. TLR9 expression in the crypt and lamina propria positively associates with C-reactive protein and IL-6 and negatively with I-FABP. TLR4 is significantly lower on surface epithelium and higher in crypts in viremic. Its expression in the lamina propria positively correlates with IL-6 and negatively correlates with I-FABP.

CONCLUSION

Mucosal TLR imbalance and deregulation, and the resulting mucosal TLR desensitization and hypervigilance, remain after suppressive ART, in the presence or absence of T-cell recovery, likely contributing to chronic systemic inflammation.

Intestinal Oxygenation and Survival After Surgery for Necrotizing Enterocolitis: An Observational Cohort Study

OBJECTIVE

To assess whether regional intestinal oxygen saturation (rintSO2) and regional cerebral oxygen saturation (rcSO2) measurements aid in estimating survival of preterm infants after surgery for NEC.

SUMMARY OF BACKGROUND DATA

Predicting survival after surgery for NEC is difficult yet of the utmost importance for counseling parents.

METHODS

We retrospectively studied prospectively collected data of preterm infants with surgical NEC who had available rintSO2 and rcSO2 values measured via near-infrared spectroscopy 0-24 hours preoperatively. We calculated mean rintSO2 and rcSO2 for 60-120 minutes for each infant. We analyzed whether preoperative rintSO2 and rcSO2 differed between survivors and non-survivors, determined cut-off points, and assessed the added value to clinical variables.

RESULTS

We included 22 infants, median gestational age 26.9 weeks [interquartile range (IQR): 26.3-28.4], median birth weight 1088 g [IQR: 730-1178]. Eleven infants died postoperatively. Preoperative rintSO2, but not rcSO2, was higher in survivors than in non-survivors [median: 63% (IQR: 42-68) vs 29% (IQR: 21-43), P < 0.01), with odds ratio for survival 4.1 (95% confidence interval, 1.2-13.9, P = 0.02) per 10% higher rintSO2. All infants with rintSO2 values of >53% survived, whereas all infants with rintSO2 <35% died. Median C-reactive protein [138 mg/L (IQR: 83-179) vs 73 mg/L (IQR: 12-98), P < 0.01), lactate [1.1 mmol/L (IQR: 1.0-1.6) vs 4.6 mmol/L (IQR: 2.8-8.0), P < 0.01], and fraction of inspired oxygen [25% (IQR: 21-31) vs 42% (IQR: 30-80), P < 0.01] differed between survivors and non-survivors. Only rintSO2 remained significant in the multiple regression model.

CONCLUSIONS

Measuring rintSO2, but not rcSO2, seems of added value to clinical variables in estimating survival of preterm infants after surgery for NEC. This may help clinicians in deciding whether surgery is feasible and to better counsel parents about their infants' chances of survival.

Predicting intestinal recovery after necrotizing enterocolitis in preterm infants

BACKGROUND

Intestinal recovery after NEC is difficult to predict in individuals. We evaluated whether several biomarkers predict intestinal recovery after NEC in preterm infants.

METHODS

We measured intestinal tissue oxygen saturation (r_intSO₂) and collected urinary intestinal-fatty acid binding protein (I-FABP_u) levels 0-24 h and 24-48 h after NEC onset, and before and after the first re-feed. We assessed intestinal recovery in two ways: time to full enteral feeding (FEFt; below or equal/above group's median) and development of post-NEC complications (recurrent NEC/post-NEC stricture). We determined whether the r_intSO₂, its range, and I-FABP_u differed between groups.

RESULTS

We included 27 preterm infants who survived NEC (Bell's stage ≥ 2). Median FEFt was 14 [IQR: 12-23] days. Biomarkers only predicted intestinal recovery after the first re-feed. Mean r_intSO₂ ≥ 53% combined with mean r_intSO_2range ≥ 50% predicted FEFt < 14 days with OR 16.7 (CI: 2.3-122.2). The r_intSO_2range was smaller (33% vs. 51%, p < 0.01) and I-FABP_u was higher (92.4 vs. 25.5 ng/mL, p = 0.03) in case of post-NEC stricture, but not different in case of recurrent NEC, compared with infants without complications.

CONCLUSION

The r_intSO₂, its range, and I-FABP_u after the first re-feed after NEC predicted intestinal recovery. These biomarkers have potential value in individualizing feeding regimens after NEC.

Urinary I-FABP, L-FABP, TFF-3, and SAA Can Diagnose and Predict the Disease Course in Necrotizing Enterocolitis at the Early Stage of Disease

Necrotizing enterocolitis (NEC) is a severe gastrointestinal disease affecting mainly preterm newborns. It is characterized by unexpected onset and rapid progression with specific diagnostic signs as pneumatosis intestinalis or gas in the portal vein appearing later in the course of the disease. Therefore, we analyzed diagnostic and prognostic potential of the markers of early NEC pathogenesis, such as excessive inflammatory response (serum amyloid A (SAA)) and gut epithelium damage (intestinal and liver fatty acid-binding protein (I-FABP and L-FABP, respectively) and trefoil factor-3 (TFF-3)). We used ELISA to analyze these biomarkers in the urine of patients with suspected NEC, either spontaneous or surgery-related, or in infants without gut surgery (controls). Next, we compared their levels with the type of the disease (NEC or sepsis) and its severity. Already at the time of NEC suspicion, infants who developed NEC had significantly higher levels of all tested biomarkers than controls and higher levels of I-FABP and L-FABP than those who will later develop sepsis. Infants who will develop surgery-related NEC had higher levels of I-FABP and L-FABP than those who will develop sepsis already during the first 6 hours after the abdominal surgery. I-FABP was able to discriminate between infants who will develop NEC or sepsis and the SAA was able to discriminate between medical and surgical NEC. Moreover, the combination of TFF-3 with I-FABP and SAA could predict pneumatosis intestinalis, and the combination of I-FABP, L-FABP, and SAA could predict gas in the portal vein or long-term hospitalization and low SAA predicts early full enteral feeding. Thus, these biomarkers may be useful not only in the early, noninvasive diagnostics but also in the subsequent NEC management.

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.

Immediate Post-operative Enterocyte Injury, as Determined by Increased Circulating Intestinal Fatty Acid Binding Protein, Is Associated With Subsequent Development of Necrotizing Enterocolitis After Infant Cardiothoracic Surgery

Objectives: 1 Measure serial serum intestinal fatty acid binding protein levels in infants undergoing cardiac surgery with cardiopulmonary bypass to evaluate for evidence of early post-operative enterocyte injury. 2 Determine the association between immediate post-operative circulating intestinal fatty acid binding protein levels and subsequent development of necrotizing enterocolitis. Design: Observational cohort study. Intestinal fatty acid binding protein was measured pre-operatively, at rewarming, and at 6 and 24 h post-operatively. Percent of goal enteral kilocalories on post-operative day 5 and episodes of necrotizing enterocolitis were determined. Multivariable analysis assessed for factors independently associated with clinical feeding outcomes and suspected/definite necrotizing enterocolitis. Setting: Quaternary free-standing children's hospital pediatric cardiac intensive care unit. Patients: 103 infants <120 days of age undergoing cardiothoracic surgery with cardiopulmonary bypass. Interventions: None. Results: Median pre-operative intestinal fatty acid binding protein level was 3.93 ng/ml (range 0.24-51.32). Intestinal fatty acid binding protein levels rose significantly at rewarming (6.35 ng/ml; range 0.54-56.97; p = 0.008), continued to rise slightly by 6 h (6.57 ng/ml; range 0.75-112.04; p = 0.016), then decreased by 24 h (2.79 ng/ml; range 0.03-81.74; p < 0.0001). Sixteen subjects (15.7%) developed modified Bell criteria Stage 1 necrotizing enterocolitis and 9 subjects (8.8%) developed Stage 2 necrotizing enterocolitis. Infants who developed necrotizing enterocolitis demonstrated a significantly higher distribution of intestinal fatty acid binding protein levels at both 6 h (p = 0.005) and 24 h (p = 0.005) post-operatively. On multivariable analysis, intestinal fatty acid binding protein was not associated with percentage of goal enteral kilocalories delivered on post-operative day 5. Higher intestinal fatty acid binding protein was independently associated with subsequent development of suspected/definite necrotizing enterocolitis (4% increase in odds of developing necrotizing enterocolitis for each unit increase in intestinal fatty acid binding protein; p = 0.0015). Conclusions: Intestinal fatty acid binding protein levels rise following infant cardiopulmonary bypass, indicating early post-operative enterocyte injury. Intestinal fatty acid binding protein was not associated with percent of goal enteral nutrition achieved on post-operative day 5, likely due to protocolized feeding advancement based on clinically observable factors. Higher intestinal fatty acid binding protein at 6 h post-operatively was independently associated with subsequent development of necrotizing enterocolitis and may help identify patients at risk for this important complication.

Gastrointestinal Failure in Critically Ill Patients With Cirrhosis

Gastrointestinal failure (GIF) is frequent in patients managed in the intensive care units and manifests as gut paralysis or ileus. GIF is often associated with sepsis or multiorgan failure. In critically ill patients, the precipitating causes of GIF include inflammation, sepsis, electrolyte abnormalities, and acidosis. It is possible that GIF is associated with an increase in bacterial translocation, especially in those with cirrhosis and portal hypertension, and this may play a significant pathogenic or prognostic role in acute-on-chronic liver failure (ACLF). The critical care literature suggests that GIF is associated with a higher mortality risk. In this review, we summarize the evidence for a potential association between GIF and ACLF and propose treatment options for the management of GIF. Moreover, we suggest GIF to be considered as another organ failure when the severity of ACLF is assessed.

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.

Surgical considerations for neonates with necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a potentially devastating condition that preferentially affects premature and low birth weight infants, with approximately half requiring acute surgical intervention. Surgical consult should be considered early on, and deterioration despite maximal medical therapy or the finding of pneumoperitoneum are the strongest indications for emergent surgical intervention. There is no clear consensus on the optimal surgical approach between peritoneal drainage and laparotomy; the best course of action likely depends on the infant's comorbidities, hemodynamic status, size, disease involvement, and available resources. Patients who develop surgical NEC are at a significant risk for morbidity and mortality, with long-term complications including short bowel syndrome, growth failure, and neurodevelopmental impairment. Further research into strategies that optimize outcomes following surgery for NEC in the neonatal intensive care unit and long-term are paramount.

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.

Is neutrophil gelatinase-associated lipocalin a good diagnostic marker for renal injury in asphyxiated preterm infants?

BACKGROUND

The objective of this study is to evaluate the value of neutrophil gelatinase-associated lipocalin (NGAL) for becoming a good endogenous marker of renal function in asphyxial preterm babies.

MATERIALS AND METHODS

This is a two-center retrospective study. Between October 2016 and October 2017, 71 asphyxial preterm infants were included in asphyxia group. Seventy babies were randomly included in control group. Samples were tested at 24, 48, and 96 h after birth. Quantitative data were compared by independent sample t-test or repeated measures ANOVA. For qualitative data, Pearson's Chi-squared test was performed. Draw ROC and compare the area under the curve (AUC), 95% confidence interval for AUC, specificity (Spe), sensitivity (Sen), and Youden index (Sen+Spe-1) at 24-h, 48-h, and 96-h time points.

RESULTS

(1) There are no significant differences concerning on baseline data. However, blood gas, Apgar score, and resuscitation showed a significant difference (P < 0.05). (2) In 24-h samples, only uNGAL and estimated glomerular filtration rate (eGFR) showed differences between the two groups (P < 0.05). In 48-h samples, significant differences could be found in uKIM-1, uNGAL, blood urea nitrogen, and eGFR (P < 0.05). In 96-h samples, almost all indicators have significant differences except urine output and eGFR (P < 0.05). (3) All biomarkers showed statistical difference in the three time points (P < 0.05), but only uNGAL showed a downward trend after the increase of expression. (4) uNGAL has better Sen and Spe than other indicators (24-h AUC 0.870, Youden index 0.606; 48-h AUC 0.879, Youden index 0.692; and 96-h AUC 0.806, Youden index 0.606).

CONCLUSION

uNGAL has a better distinguishability in asphyxial neonates compared with other indicators. Certainly, a larger sample, prospective study is still needed.

Current status of laboratory and imaging diagnosis of neonatal necrotizing enterocolitis

Necrotizing enterocolitis continues to be a devastating disease process for very low birth weight infants in Neonatal Intensive Care Units. The aetiology and pathogenesis of necrotizing enterocolitis are not definitively understood. It is known that necrotizing enterocolitis is secondary to a complex interaction of multiple factors that results in mucosal damage, which leads to intestinal ischemia and necrosis. Advances in neonatal care, including resuscitation and ventilation support technology, have seen increased survival rates among premature neonates and a concomitant detection in the incidence of this intestinal disease.Diagnosis can be difficult, and identifying infants at the onset of disease remains a challenge. Early diagnosis, which relies on imaging findings, and initiation of prompt therapy are essential to limit morbidity and mortality. Moreover, early management is critical and life-saving.This review summarizes what is known on the laboratory and instrumental diagnostic strategies needed to improve neonatal outcomes and, possibily, to prevent the onset of an overt necrotizing enterocolitis.

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.

Serum (1→3)-β-D-glucan and galactomannan levels in patients with cystic fibrosis: a retrospective cohort study

Background

Aspergillus fumigatus is frequently encountered in sputum samples of patients with cystic fibrosis (CF), which traditionally has been interpreted as saprophytic airway colonization. However, this mere bystander role has been challenged by recent data. There is now evidence that Aspergillus fumigatus accelerates the decline of pulmonary function.

(1→3)-β-D-glucan (BDG) and galactomannan (GM) are highly sensitive fungal biomarkers that are used to diagnose invasive fungal disease. However, their diagnostic value in CF patients is largely unknown.

Methods

We conducted a retrospective cohort study on 104 CF patients to determine whether serum BDG and GM levels correlate with parameters such as Aspergillus-positive sputum cultures and lung function.

Results

Aspergillus fumigatus was persistently detected in 22 of the 104 CF patients (21%). Mean serum BDG and GM levels in the Aspergillus-positive patients were significantly higher than in those without persistent Aspergillus detection (89 versus 40 pg/ml [p = 0.022] and 0.30 versus 0.15 ODI [p = 0.013], respectively). 27 and 7 patients had elevated BDG (≥ 60 pg/ml) or GM levels (> 0.5 ODI), respectivly. BDG and GM levels showed a significant correlation (p = 0.004). Patients with increased serum concentrations of BDG were more frequently Aspergillus-positive (40.7 versus 14.3%, p = 0.004) and had a significantly lower forced expiratory volume in one second (FEV1) than patients with a normal BDG (61.6 versus 77.1%, p = 0.007). In the multivariate analysis, BDG but not GM or the growth of A. fumigatus, proved to be an independent predictor for the FEV1.

Conclusions

CF patients with persistent Aspergillus detection have elevated BDG and GM levels which ranged between healthy and invasively infected patients. Serum BDG may be superior to GM and fungal culture in predicting an impaired lung function in CF patients.

Breastmilk cell trafficking induces microchimerism-mediated immune system maturation in the infant

Initiating breastfeeding within the first hour of life confers an important benefit in terms of child mortality and severe morbidity. Intestinal permeability to ingested macromolecules and immunoglobulins is limited to the first days of human life. These exchanges cease in the very early post-partum period but may increase beyond the neonatal period in response to local inflammation or introduction of a weaning food. From animal- and limited human-based observations, compelling evidence points out to breastmilk cells also trafficking from mother to infant mucosal tissues and participating to the maternal microchimerism. The precise nature of breastmilk cells that are involved is presently not known but likely includes progenitor/stem cells-representing up to 6% of breastmilk cells-with possible contribution of mature immune cells. Stem cell microchimerism may induce tolerance to non-inherited maternal antigens (NIMAs), breastfeeding generating regulatory T cells (T_reg ) that suppress antimaternal immunity. Therefore, in complement to pregnancy-induced microchimerism, breastfeeding-induced microchimerism may be pivotal in infant immune development, intestinal tissue repair/growth and protection against infectious diseases. As a continuum of the gestational period, the neonatal gut may be considered as a temporary, but important developmental extension of the role played by the placenta during intrauterine life; breastmilk playing the role of maternal blood by delivering maternal soluble factors (macromolecules, Ig, cytokines) and immunologically active milk cells. A better understanding of breastfeeding-induced maternal microchimerism would provide further evidence in support of public health messages that reinforce the importance of early initiation of breastfeeding.

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.

Significance of dynamic evolution of TNF-α, IL-6 and intestinal fatty acid-binding protein levels in neonatal necrotizing enterocolitis

To study the significance of dynamic evolution of serum tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6) and intestinal fatty acid-binding protein (I-FABP) levels in neonatal necrotizing enterocolitis (NEC). A total of 45 NEC child patients, 45 non-NEC child patients and 45 healthy newborns were enrolled. After the day age, weight, gestational week and delivery mode were matched, the serum TNF-α, IL-6 and I-FABP levels at 6, 24 and 72 h after admission were measured via ELISA method, and their correlations with prognosis were analyzed. The levels of serum TNF-α and IL-6 in NEC and non-NEC group reached the peak at 24 h and fell at 72 h; there were no differences in each time point between the two groups (P>0.05), but the levels of serum TNF-α and IL-6 were higher than those in the control group (P<0.05). The level of serum I-FABP in NEC and non-NEC group reached the peak at 6 h, and it fell at 72 h in NEC group and 24 h in non-NEC group; the level of I-FABP in each time point in NEC was significantly higher than that in non-NEC group, and the level was the lowest in healthy group; the differences were statistically significant (P<0.05). There were 40 cases of survival and 5 cases of death (11.1%) in NEC group, while there were 43 cases of survival and 2 cases of death (4.4%) in non-NEC group. There were no differences in serum TNF-α and IL-6 levels at different times between surviving child patients and dead child patients in NEC group (P>0.05), but the levels of serum I-FABP in surviving child patients at 6 h and 24 h were significantly lower than those in dead child patients (P<0.05), and there was no difference at 72 h (P>0.05). There were no differences in serum TNF-α, IL-6 and I-FABP levels at different times between surviving and dead child patients in non-NEC group (P>0.05). Serum I-FABP level and its dynamic evolution may be important indexes of early diagnosis and prognosis evaluation of NEC.

Advances in paediatric gastroenterology

Recent developments in paediatric gastrointestinal surgery have focused on minimally invasive surgery, the accumulation of high-quality clinical evidence, and scientific research. The benefits of minimally invasive surgery for common disorders like appendicitis and hypertrophic pyloric stenosis are all supported by good clinical evidence. Although minimally invasive surgery has been extended to neonatal surgery, it is difficult to establish its role for neonatal disorders such as oesophageal atresia and biliary atresia through clinical trials because of the rarity of these disorders. Advances in treatments for biliary atresia and necrotising enterocolitis have been achieved through specialisation, multidisciplinary management, and multicentre collaboration in research; similarly robust clinical evidence for other rare gastrointestinal disorders is needed. As more neonates with gastrointestinal diseases survive into adulthood, their long-term sequelae will also need evidence-based multidisciplinary care. Identifying cures for long-term problems of a complex developmental anomaly such as Hirschsprung's disease will rely on unravelling its pathogenesis through genetics and the development of stem-cell therapy.