Incidence and risk of necrotizing enterocolitis in Denmark from 1994-2014

Value of portal venous gas and a nomogram for predicting severe neonatal necrotizing enterocolitis

BACKGROUND

Whether portal venous gas (PVG) is a sign of severe neonatal necrotizing enterocolitis (NEC) and predicts poor prognosis remains uncertain.

METHODS

Patients from two centres were randomly assigned to a training set or a validation set. A nomogram model for predicting severe NEC was developed on the basis of the independent risk factors selected by least absolute shrinkage and selection operator (LASSO) regression analysis and multivariate logistic regression analysis. The model was evaluated based on the area under the curve (AUC), calibration curve, and decision curve analysis (DCA).

RESULTS

A total of 585 patients met the study criteria, and propensity score matching resulted in 141 matched pairs for further analysis. Patients with PVG had a greater risk of surgical intervention or death compared with patients without PVG. A prediction model for severe NEC was established based on PVG, invasive mechanical ventilation (IMV), serum platelet count (PLT) and pH <7.35 at the onset of NEC. The model had a moderate predictive value with an AUC > 0.8. The calibration curve and DCA suggested that the nomogram model had good performance for clinical application.

CONCLUSION

A prediction nomogram model based on PVG and other risk factors can help physicians identify severe NEC early and develop reasonable treatment plans.

IMPACT

PVG is an important and common imaging manifestation of NEC. Controversy exists regarding whether PVG is an indication for surgical intervention and predicts poor prognosis. Our study suggested that patients with PVG had a greater risk of surgical intervention or death compared with patients without PVG. PVG, IMV, PLT and pH <7.35 at the onset of NEC are independent risk factors for severe NEC. A prediction nomogram model based on PVG and other risk factors may help physicians identify severe NEC early and develop reasonable treatment plans.

Peripheral Lymphocyte Changes Associate With the Progression of Necrotizing Enterocolitis in Infants

INTRODUCTION

Immune factors are important antecedents in the pathophysiology of necrotizing enterocolitis (NEC). However, studies on the peripheral blood lymphocyte subsets changes in NEC patients among different Bell stages and in patients requiring surgery are scarce.

METHODS

34 infants with NEC and 33 age-matched controls were included. Peripheral blood was collected within 48 h after NEC diagnosis. Peripheral blood B and T lymphocytes subsets were detected by 12-color flow cytometry. Cell ratios were calculated, and their relationship to disease severity and their roles as indicators for surgery were assessed.

RESULTS

NEC patients showed elevated percentages of unSwB cells (CD27+IgD+ unswitched memory/activated B cells)/B cells, SwB cells (CD27+IgD-switched memory B cells)/B cells, CD8+ T (CD3+CD8+ T cells)/T cells, Tem (CD45RA-CCR7-effector memory T cells)/CD4+ T cells, Tem/CD8+ T cells and decreased Bn (CD27-IgD+ naïve B cells)/B cells, CD4+T (CD3+CD4+ T cells)/T cells, CD45RA+ CCR7+ naïve T cells (CD45RA+CCR7+ naïve T cells)/CD8+T cells. Compared to NEC patients at BELL stage I + II, patients at BELL stage III showed increased percentages of SwB cells/B cells, antibody secreting cell (ASC, CD3-CD20-CD27high CD38high ASCs)/B cells and Tem/CD4+ T cells, and decreased percentages of CD45RA+CCR7+ naïve T cells/CD4+ T cells. The Receiver Operating Characteristic Curve analysis showed that the sensitivity of ASC/B cells ratio (0.52%) is 86.67% and the specificity of Tem/CD4+T ratio (5.22%) is 100%, indicating that NEC patients required surgery.

CONCLUSIONS

The severity of NEC exhibits codirectional changes with the maturation of B and T lymphocytes, especially CD4+ T cells. The increased ASC/B and Tem/CD4+ T cells could serve as potential indicators for NEC patients requiring surgery.

Value of near-infrared spectroscopy in evaluating the risk of neonatal necrotizing enterocolitis: A systematic review and meta-analysis

PURPOSE

Recently, near-infrared spectroscopy (NIRS) has been proposed for diagnosing patients with neonatal necrotizing enterocolitis (NEC). However, a consensus on the credibility of NIRS in evaluating NEC risk has not been reached. This meta-analysis aimed to evaluate the relationship between NEC and splanchnic regional tissue oxygen saturation (SrSO2) and cerebral regional tissue oxygen saturation (CrSO2) detected by NIRS to clarify the clinical value of NIRS in evaluating the risk of NEC.

METHODS

Studies using NIRS to monitor regional tissue oxygen saturation (rSO2) in neonates with NEC published in PubMed, Web of Science, Embase, and the Cochrane Library were searched from their inception to 30 July 2023. Mean difference (MD), pooled sensitivity, and pooled specificity, along with their 95 % confidence intervals (CI), were calculated, and the random-effects model was used for analysis. This study was registered with PROSPERO (no. CRD42022326783).

RESULTS

Fourteen studies including 938 neonates (172 NEC, 766 controls) were identified. SrSO2 was significantly decreased in patients with NEC (MD: -12.52, 95 % CI: -15.95, -9.08; P < 0.00001), and this decrease was observed even before the diagnosis of NEC (MD: -13.79, 95 % CI: -17.97, -9.62; P < 0.00001). The pooled sensitivity and specificity of SrSO2 were 0.80 (95 % CI: 0.69, 0.88) and 0.90 (95 % CI: 0.61, 0.98), respectively. However, no significant difference in CrSO2 was found (MD: -4.37, 95 % CI: -10.62, 1.88; P = 0.17).

CONCLUSIONS

SrSO2, detected by NIRS, could be a valuable non-invasive method for differentiating NEC from non-NEC neonates. It could differentiate prior to NEC diagnosis.

The gut microbiome, resistome, and mycobiome in preterm newborn infants and mouse pups: lack of lasting effects by antimicrobial therapy or probiotic prophylaxis

BACKGROUND

Enhancing our understanding of the underlying influences of medical interventions on the microbiome, resistome and mycobiome of preterm born infants holds significant potential for advancing infection prevention and treatment strategies. We conducted a prospective quasi-intervention study to better understand how antibiotics, and probiotics, and other medical factors influence the gut development of preterm infants. A controlled neonatal mice model was conducted in parallel, designed to closely reflect and predict exposures. Preterm infants and neonatal mice were stratified into four groups: antibiotics only, probiotics only, antibiotics followed by probiotics, and none of these interventions. Stool samples from both preterm infants and neonatal mice were collected at varying time points and analyzed by 16 S rRNA amplicon sequencing, ITS amplicon sequencing and whole genome shotgun sequencing.

RESULTS

The human infant microbiomes showed an unexpectedly high degree of heterogeneity. Little impact from medical exposure (antibiotics/probiotics) was observed on the strain patterns, however, Bifidobacterium bifidum was found more abundant after exposure to probiotics, regardless of prior antibiotic administration. Twenty-seven antibiotic resistant genes were identified in the resistome. High intra-variability was evident within the different treatment groups. Lastly, we found significant effects of antibiotics and probiotics on the mycobiome but not on the microbiome and resistome of preterm infants.

CONCLUSIONS

Although our analyses showed transient effects, these results provide positive motivation to continue the research on the effects of medical interventions on the microbiome, resistome and mycobiome of preterm infants.

Early antibiotic use and incidence of necrotising enterocolitis in very preterm infants: a protocol for a UK based observational study using routinely recorded data

INTRODUCTION

Necrotising enterocolitis (NEC) remains a major contributor to preterm mortality and morbidity. Prolonged duration of antibiotic therapy after delivery is associated with later NEC development but recent evidence suggests that absence of antibiotic treatment after delivery may also increase NEC risk. We will explore this controversy using a large pre-existing dataset of preterm infants in the UK.

METHODS AND ANALYSIS

This is a retrospective cohort study using data from UK National Neonatal Research Database (NNRD) for infants born 1 January 2012 to 31 December 2020. Eligible infants will be <32 weeks gestation, alive on day 3. Primary outcome is development of severe NEC, compared in infants receiving early antibiotics (days 1-2 after birth) and those not. Subgroup analysis on duration of early antibiotic exposure will also occur. Secondary outcomes are: late onset sepsis, total antibiotic use, predischarge mortality, retinopathy of prematurity, intraventricular haemorrhage, bronchopulmonary dysplasia, focal intestinal perforation and any abdominal surgery. To address competing risks, incidence of death before day 7, 14 and 28 will be analysed. We will perform logistic regression and propensity score matched analyses. Statistical analyses will be guided by NEC risk factors, exposures and outcome presented in a causal diagram. These covariates include but are not limited to gestational age, birth weight, small for gestational age, sex, ethnicity, delivery mode, delivery without labour, Apgar score, early feeding and probiotic use. Sensitivity analyses of alternate NEC definitions, specific antibiotics and time of initiation will occur.

ETHICS AND DISSEMINATION

We will use deidentified data from NNRD, which holds permissions for the original data, from which parents can opt out and seek study-specific research ethics approval. The results will help to determine optimal use of early antibiotics for very preterm infants.

IMPLICATIONS

This data will help optimise early antibiotic use in preterm infants.

TRIAL REGISTRATION NUMBER

ISRCTN55101779.

Blood transcriptomic markers of necrotizing enterocolitis in preterm pigs

BACKGROUND

Necrotizing enterocolitis (NEC), a severe gut disorder in preterm infants, is difficult to predict due to poor specificity and sensitivity of clinical signs and biomarkers. Using preterm piglets as a model, we hypothesized that early development of NEC affects blood gene expression, potentially related to early systemic immune responses.

METHODS

A retrospective analysis of clinical, tissue, and blood data was performed on 129 formula-fed piglets with NEC diagnosis at necropsy on day 5. Subgroups of NEC (n = 20) and control piglets (CON, n = 19) were analyzed for whole-blood transcriptome.

RESULTS

Preterm piglets had variable NEC lesions, especially in the colon region, without severe clinical signs (e.g. normal growth, activity, hematology, digestion, few piglets with bloody stools). Transcriptome analysis showed 344 differentially expressed genes (DEGs) between NEC and CON piglets. Validation experiment showed that AOAH, ARG2, FKBP5, PAK2, and STAT3 were among the genes affected by severe lesions on day 5, when analyzed in whole blood and in dried blood spots (DBS).

CONCLUSION

Whole-blood gene expressions may be affected in preterm pigs before clinical signs of NEC get severe. Blood gene expression analysis, potentially using DBS samples, is a novel tool to help identify new early biomarkers of NEC.

IMPACT

Preterm pig model was used to investigate if blood transcriptomics could be used to identify new early blood biomarkers of NEC progression. Whole-blood transcriptome revealed upregulation of target genes in NEC cases when clinical symptoms are subtle, and mainly colon regions were affected. Differential NEC-associated gene expressions could be detected also in dried blood spots, potentially allowing easy collection of small blood volumes in infants.

Altered microstructure of the splenium of corpus callosum is associated with neurodevelopmental impairment in preterm infants with necrotizing enterocolitis

Background

Necrotizing enterocolitis (NEC) is a devastating disease in preterm infants with significant morbidities, including neurodevelopmental impairment (NDI). This study aimed to investigate whether NEC is associated with (1) brain volume expansion and white matter maturation using diffusion tensor imaging analysis and (2) NDI compared with preterm infants without NEC.

Methods

We included 86 preterm infants (20 with NEC and 66 without NEC) with no evidence of brain abnormalities on trans-fontanelle ultrasonography and magnetic resonance imaging at term-equivalent age (TEA). Regional brain volume analysis and white matter tractography were performed to study brain microstructure alterations. NDI was assessed using the Bayley Scales of Infant and Toddler Development-III (BSID-III) at 18 months of corrected age (CA).

Results

Preterm infants with NEC showed significantly high risk of motor impairment (odds ratio 58.26, 95% confidence interval 7.80–435.12, p < 0.001). We found significantly increased mean diffusivity (MD) in the splenium of corpus callosum (sCC) (p = 0.001) and the left corticospinal tract (p = 0.001) in preterm infants with NEC. The sCC with increased MD showed a negative association with the BSID-III language (p = 0.025) and motor scores (p = 0.002) at 18 months of CA, implying the relevance of sCC integrity with later NDI.

Conclusion

The white matter microstructure differed between preterm infants with and without NEC. The prognostic value of network parameters of sCC at TEA may provide better information for the early detection of NDI in preterm infants.

Near-infrared spectroscopy as a diagnostic tool for necrotizing enterocolitis in preterm infants

BACKGROUND

We aimed to investigate whether splanchnic tissue oxygen saturation (r_sSO₂) measured by near-infrared spectroscopy (NIRS) could contribute to the early diagnosis of necrotizing enterocolitis (NEC).

METHODS

We retrospectively included infants with suspected NEC, gestational age <32 weeks and/or birth weight <1200 g in the first 3 weeks after birth. We calculated mean r_sSO₂, cerebral tissue oxygen saturation (r_cSO₂), variability of r_sSO₂ (coefficients of variation [r_sCoVAR] = SD/mean), and splanchnic-cerebral oxygenation ratio ([SCOR] = r_sSO₂/r_cSO₂) in the period around the abdominal radiograph to confirm or reject NEC.

RESULTS

Of the 75 infants, 21 (28%) had NEC (Bell's stage ≥2). Characteristics of infants with and without NEC differed only on mechanical ventilation and nil-per-os status. R_sSO₂ tended to be higher and r_cSO₂ lower in infants with NEC. R_sCoVAR (median [range]) was lower (0.11 [0.03-0.34]) vs. 0.20 [0.01-0.52], P = 0.002) and SCOR higher (0.64 [0.37-1.36]) vs. 0.47 [0.16-1.09], P = 0.004) in NEC infants. Adjusted for postnatal age, mechanical ventilation, and nil-per-os status, a 0.1 higher r_sCoVAR decreased the likelihood of NEC diagnosis with likelihood ratio (LR) 0.38 (95% CI 0.18-0.78) and a 0.1 higher SCOR increased it with LR 1.28 (1.02-1.61).

CONCLUSIONS

Using NIRS, high SCOR may confirm NEC and high variability of r_sSO₂ may rule out NEC, when suspicion arises.

IMPACT

Near-infrared spectroscopy may contribute to the diagnosis of necrotizing enterocolitis. When clinical signs are present a high splanchnic-cerebral oxygenation may indicate necrotizing enterocolitis. A low splanchnic-cerebral oxygenation ratio and high variability of splanchnic tissue oxygen saturation may rule out necrotizing enterocolitis. Whether a bedside real-time availability of the splanchnic-cerebral oxygenation ratio and variability of splanchnic tissue oxygen saturation improves NEC diagnosis needs to be further investigated.

Long-term digestive hospitalizations of premature infants (besides necrotizing enterocolitis): is there a critical threshold?

BACKGROUND

In this study we sought to ascertain a critical threshold of the degree of prematurity and long-term digestive morbidity of the offspring.

METHODS

A population-based cohort analysis was conducted, comparing long-term incidence of digestive morbidity in infants born preterm. Cases were divided into four groups according to the extremity of prematurity. Digestive morbidity included hospitalizations involving a predefined set of ICD9 codes. A Kaplan-Meier survival curve was constructed to compare cumulative incidence of digestive morbidity. A Cox proportional hazards model was used to control for confounders.

RESULTS

During the study period 220,563 patients met the inclusion criteria. Offspring born preterm had significantly more hospitalizations due to digestive morbidity compared to term offspring. The Kaplan-Meier survival curve demonstrated significant higher cumulative incidence of long-term digestive morbidity of the offspring with decreasing gestational age (Log rank p < 0.001). The risk was highest at 28 weeks gestation. Using a Cox proportional hazards model, being born at very and moderate to late preterm birth was independently associated with long-term digestive morbidity.

CONCLUSION

Preterm delivery is an independent risk factor for long-term digestive morbidity of the offspring. In our population, 28 weeks gestation is the critical cut-off for pronounced digestive morbidity.

Survival of Ventilated Extremely Premature Neonates With Severe Intraventricular Hemorrhage

BACKGROUND

Severe intraventricular hemorrhage (IVH) is a leading mortality risk factor among extremely premature neonates. Because other life-threatening conditions also occur in this population, it is unclear whether severe IVH is independently associated with death. The existence and potential implications of regional variation in severe IVH-associated mortality are unknown.

METHODS

We performed a retrospective cohort study of mechanically ventilated neonates born at 22 to 29 weeks' gestation who received care in 242 American NICUs between 2000 and 2014. After building groups composed of propensity score-matched and center-matched pairs, we used the Cox proportional hazards analysis to test our hypothesis that severe IVH would be associated with greater all-cause in-hospital mortality, defined as death before transfer or discharge. We also performed propensity score-matched subgroup analyses, comparing severe IVH-associated mortality among 4 geographic regions of the United States.

RESULTS

In our analysis cohort, we identified 4679 patients with severe IVH. Among 2848 matched pairs, those with severe IVH were more likely to die compared with those without severe IVH (hazard ratio 2.79; 95% confidence interval 2.49-3.11). Among 1527 matched pairs still hospitalized at 30 days, severe IVH was associated with greater risk of death (hazard ratio 2.03; 95% confidence interval 1.47-2.80). Mortality associated with severe IVH varied substantially between geographic regions.

CONCLUSIONS

The early diagnosis of severe IVH is independently associated with all-cause in-hospital mortality in extremely premature neonates. Regional variation in severe IVH-associated mortality suggests that shared decision-making between parents and neonatologists is strongly influenced by ultrasound-based IVH assessment and classification.

Early Use of Antibiotics Is Associated with a Lower Incidence of Necrotizing Enterocolitis in Preterm, Very Low Birth Weight Infants: The NEOMUNE-NeoNutriNet Cohort Study

OBJECTIVE

To determine whether commencement of antibiotics within 3 postnatal days in preterm, very low birth weight (VLBW; ≤1500 g) infants is associated with the development of necrotizing enterocolitis (NEC).

STUDY DESIGN

Preplanned statistical analyses were done to study the association between early antibiotic treatment and later NEC development, using the NEOMUNE-NeoNutriNet cohort of VLBW infants from 13 neonatal intensive care units (NICUs) in 5 continents (n = 2831). NEC incidence was compared between infants who received early antibiotics and those who did not, with statistical adjustments for NICU, gestational age, birth weight, sex, delivery mode, antenatal steroid use, Apgar score, and type and initiation of enteral nutrition.

RESULTS

The incidence of NEC was 9.0% in the group of infants who did not receive early antibiotics (n = 269), compared with 3.9% in those who did receive early antibiotics (n = 2562). The incidence remained lower in the early antibiotic group after stepwise statistical adjustments for NICU (OR, 0.57; 95% CI, 0.35-0.94, P < .05) and other potential confounders (OR, 0.25; 95% CI, 0.12-0.47; P < .0001).

CONCLUSIONS

In this large international cohort of preterm VLBW infants, a small proportion of infants did not receive antibiotics just after birth, and these infants had a higher incidence of NEC. It is important to better understand the role of such variables as time, type, and duration of antibiotic treatment on NEC incidence, immune development, gut colonization, and antibiotic resistance in the NICU.

Fecal microbiota transplantation by enema reduces intestinal injury in experimental necrotizing enterocolitis

PURPOSE

Necrotizing Enterocolitis (NEC) is a devastating neonatal disease with a high mortality rate. Fecal Microbiota Transplantation (FMT) has been used to treat a variety of gastrointestinal diseases. We aimed to investigate the role of FMT in NEC.

METHODS

NEC was induced by hypoxia, LPS, and hyperosmolar gavage feeding between postnatal days P5 and P9 (n = 8). Breastfed mice were used as control (n = 7). FMT (30 μl/g) was administered by gavage or enema at P6 during NEC induction. Distal ileum was harvested on P9. Disease severity was evaluated by H&E staining. Gene expression of inflammatory markers IL6 and TNFa was measured. Expression of intestinal barrier function was investigated by measuring Claudin-7. Microbiota composition in ileum and colon was analyzed by quantitative PCR.

RESULTS

FMT by gavage further increased terminal ileum inflammation and did not improve the histological damage owing to experimental NEC. Conversely, FMT by enema decreased intestinal inflammation and improved histology of the NEC-like injury in the ileum. In addition, compared with NEC alone, FMT by enema increased Claudin-7 expression indicating an improvement in barrier function. These beneficial effects occurred despite no change in microbiota.

CONCLUSION

Our results show that FMT by enema may be an effective strategy to reduce NEC progression as it attenuates intestinal inflammation and enhances intestinal barrier function. FMT by enema is a potential novel treatment for NEC.

LEVEL OF EVIDENCE

Level IV, Evidence from well-designed case-control or cohort studies.

Beneficial effects of butyrate in intestinal injury

PURPOSE

Butyrate is a short-chain fatty acid produced in the intestine. It is controversial whether butyrate is protective or destructive for the intestinal epithelium in the development of diseases like necrotizing enterocolitis (NEC), and its mechanism of action remains unclear. We aimed to determine the effect of butyrate on the intestinal epithelium by studying its effects on intestinal epithelial cells (IEC-18) exposed to injury and in vivo by investigating the effects on the intestine in an experimental model of NEC.

METHODS

A) In vitro study: Butyrate was given to normal IEC-18 to determine the dose triggering injury. Based on above results, low dose butyrate (1 mM) was given to H₂O₂-injured cells to determine its effect against inflammation. B) In vivo study: NEC was induced by hypoxia and gavage feeding between postnatal day P5 and P9 (n = 8). Breastfed mice were used as control (n = 7). Butyrate (150 mM) was administered by enema on P6 in NEC (n = 6). Distal ileum was harvested on P9.

RESULTS

High dose (16 mM) butyrate upregulated inflammatory marker IL-6, while low dose butyrate protected cells from injury by reducing IL-6 expression. Similarly, compared with NEC alone, NEC mice who received butyrate had reduced intestinal damage, reduced IL-6 and NF-ĸB expression, and increased intestinal tight junction marker Claudin-7.

CONCLUSION

Butyrate has opposite effects depending on the dose administered. Butyrate can protect cells from H₂O₂-induced injury and can in vivo protect the intestine from NEC. This beneficial effect is because of downregulation of inflammation and enhancement of intestinal barrier.

Jungen sterben häufiger an nekrotisierender Enterokolitis

Hintergrund

In den letzten Jahren verringerte sich die frühgeburtliche Morbidität und Mortalität über Ländergrenzen hinweg deutlich. Allen Untersuchungen gemeinsam ist aber eine höhere Betroffenheit und Sterblichkeit von Jungen gegenüber Mädchen, insbesondere bei der nekrotisierenden Enterokolitis.

Fragestellung

Besteht in Deutschland auf Basis der amtlichen Krankenhausstatistik eine höhere Inzidenz oder Sterblichkeit von Jungen an nekrotisierender Enterokolitis?

Material und Methoden

Die Autoren werteten die Diagnosedaten der amtlichen Krankenhausstatistik für die Jahre 2000–2017 für die Hauptdiagnose P77 – nekrotisierende Enterokolitis –, getrennt nach Geschlechtern und Überleben, aus. Der Zusammenhang zwischen Geschlecht und Versterben resp. Erkrankungshäufigkeit wurde mittels einseitigem χ2-Test auf ein höheres Risiko für Jungen untersucht.

Ergebnisse

Zwischen 2000 und 2017 hatten 3119 Frühgeborene die Hauptdiagnose nekrotisierende Enterokolitis, davon 1769 Jungen (0,27 ‰ der männlichen Lebendgeburten) und 1350 Mädchen (0,22 ‰ der weiblichen Lebendgeburten). Jungen haben ein höheres Risiko, an nekrotisierender Enterokolitis zu erkranken (relatives Risiko 1,24, 95 %-Konfidenzintervall: 1,17–∞, p < 0,001) und zu versterben (relatives Risiko 1,25, 95 %-Konfidenzintervall: 1,02–∞, p = 0,036).

Diskussion

Jungen erkranken und sterben häufiger an nekrotisierender Enterokolitis als Mädchen. Allerdings erfasst die amtliche Statistik nicht die leichteren Fälle einer nekrotisierenden Enterokolitis, da nur die Hauptdiagnose erfasst wird. Überdies ermöglicht die amtliche Statistik keine Adjustierung für verzerrende Faktoren. Die sekundäre Datennutzung der Qualitätssicherungsdaten der Neonatalerhebung könnte eine detailliertere Untersuchung dieser Fragestellung ermöglichen.

Supplemental Insulin-Like Growth Factor-1 and Necrotizing Enterocolitis in Preterm Pigs

Background: Recombinant human IGF-1/binding protein-3 (rhIGF-1/BP-3) is currently tested as a therapy in preterm infants but possible effects on the gut, including necrotizing enterocolitis (NEC), have not been tested. The aim of this study was to evaluate if rhIGF-1/BP-3 supplementation in the first days after birth negatively affects clinical variables like growth, physical activity, blood chemistry and hematology and gut maturation (e.g., intestinal permeability, morphology, enzyme activities, cytokine levels, enterocyte proliferation, NEC lesions), using NEC-sensitive preterm pigs as a model for preterm infants. Methods: Preterm pigs were given twice daily subcutaneous injections of rhIGF-1/BP-3 or vehicle. Blood was collected for IGF-1 measurements and gut tissue for NEC evaluation and biochemical analyses on day 5. Results: Baseline circulating IGF-1 levels were low in preterm pigs compared with near-term pigs reared by their mother (<20 vs. 70 ng/ml). Injection with rhIGF-1/BP-3 resulted in increased plasma IGF-1 levels for up to 6 h after injection (>40 ng/mL). rhIGF-1/BP-3 treatment reduced the incidence of severe NEC lesions (7/24 vs.16/24, p = 0.01) and overall NEC severity (1.8 ± 0.2 vs. 2.6 ± 0.3, p < 0.05, with most lesions occurring in colon). In the small intestine, villi length (405 ± 25 vs. 345 ± 33 μm) and activities of the brush border peptidases aminopeptidase N and dipeptidylpeptidase IV were increased in rhIGF-1/BP-3 treated pigs, relative to control pigs (+31-44%, both p < 0.05). The treatment had no effects on body weight, blood chemistry or hematology, except for an increase in blood leucocyte and neutrophil counts (p < 0.05, i.e., reduced neonatal neutropenia). Likewise, rhIGF-1/BP-3 treatment did not affect intestinal tissue cytokine levels (IL-1β, IL-6, IL-8, TNFα,), enterocyte proliferation, goblet cell density, permeability or bacterial translocation to the bone marrow. Conclusion: Supplemental rhIGF-1/BP-3 did not negatively affect any of the measured variables of clinical status or gut maturation in preterm pigs. Longer-term safety and efficacy of exogenous rhIGF-1/BP-3 to support maturation of the gut and other critical organs in preterm newborns remain to be investigated in both pigs and infants.