Models of necrotizing enterocolitis

Visceral Pain in Preterm Infants with Necrotizing Enterocolitis: Underlying Mechanisms and Implications for Treatment

Necrotizing enterocolitis (NEC) is a relatively rare but very severe gastrointestinal disease primarily affecting very preterm infants. NEC is characterized by excessive inflammation and ischemia in the intestines, and is associated with prolonged, severe visceral pain. Despite its recognition as a highly painful disease, current pain management for NEC is often inadequate, and research on optimal analgesic therapy for these patients is lacking. Insight into the mechanisms underlying intestinal pain in infants with NEC-visceral pain-could help identify the most effective analgesics for these vulnerable patients. Therefore, this comprehensive review aims to provide an overview of visceral nociception, including transduction, transmission, modulation, and experience, and discuss the implications for analgesic therapy in preterm infants with NEC. The transmission of visceral pain differs from that of somatic pain, contributing to the diffuse nature of visceral pain. Studies evaluating the effectiveness of analgesics for treating visceral pain in infants are scarce. However, research in visceral pain models highlights agents that may be particularly effective for treating visceral pain based on their mechanisms of action. Further research is necessary to determine whether agents that have shown promise for treating visceral pain in preclinical studies and adults are effective in infants with NEC as well.

Administration of Adipose-Derived Stem Cells After the Onset of the Disease Does Not Lower the Levels of Inflammatory Cytokines IL1 and IL6 in a Rat Model of Necrotizing Enterocolitis

Background/Objectives: Research on the roles of stem cells in necrotizing enterocolitis (NEC) has primarily focused on the effects of bone marrow- and amniotic fluid-derived stem cells in mitigating the clinical manifestations of the disease. However, the potential of adipose tissue-derived stem cells (ADSCs) remains unexplored in this context. The aim of this study was to evaluate the therapeutic potential of ADSC administration during the active inflammatory phase of NEC, with a specific focus on reducing the levels of the inflammatory cytokines IL-1 and IL-6. Methods: A self-modified hypoxia-hypothermia-formula feeding rat NEC model was employed. A total of 117 rat pups were divided into two groups: a treatment group (NEC-ADSC, n = 55) and a control group (NEC-PLCB (placebo), n = 62). In the NEC-ADSC group, ADSCs were administered intraperitoneally 24 h into the NEC protocol. After 72 h, bowel and fluid samples were collected for analysis. Results: The analysis revealed no significant effect on NEC histopathology (p = 0.347) or on the levels of IL-1 and IL-6 (p = 0.119 and p = 0.414, respectively). Conclusions: The administration of adipose tissue-derived stem cells after the onset of necrotizing enterocolitis does not reduce the levels of inflammatory cytokines IL-1 and IL-6, nor does it influence the histopathological outcomes of the disease in the rat model. Further research is needed to explore the potential therapeutic role of adipose tissue-derived stem cells in the treatment of necrotizing enterocolitis.

A weighted and cumulative point system for accurate scoring of intestinal pathology in a piglet model of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a serious condition in premature infants, in which a portion of the intestine undergoes inflammation and necrosis. The preterm pig develops NEC spontaneously, making it a suitable model for exploring novel NEC treatments. We aimed to revise the intestinal scoring system to more accurately describe the diversity of NEC lesions in the preterm piglet model. We included 333 preterm piglets from four experiments, each delivered via cesarean section. The piglets were fed either a gently processed (GP) or harshly processed (HP) milk formula for 96 h before euthanasia. At necropsy, the gastrointestinal tract was assessed with 1) an established 6-grade score and 2) a descriptive approach focusing on the distribution and severity of hyperemia, hemorrhage, pneumatosis intestinalis (intramural gas), and necrosis. Subsequently, the descriptive registrations were converted into a weighted and cumulative point (WCP) score. Compared to the 6-grade score, the WCP score enabled a greater segregation of severity levels, especially among organs with more prominent NEC lesions. IL-1β in small intestinal lesions and both IL-8 and IL-1β in colon lesions correlated positively with the WCP scale. A histopathological grade system (0-8) was established and revealed mucosal pathology in lesion biopsies, which were not recognized macroscopically. Finally, the WCP score showed a higher NEC-promoting effect of the HP formula compared to the GP formula. The descriptive registrations and extended score range of this revised intestinal scoring system enhance the accuracy of describing NEC lesions in preterm pigs. This approach may increase the efficiency of preclinical NEC experiments.

Clinical Predictors of Spontaneous Intestinal Perforation vs Necrotizing Enterocolitis in Extremely and Very Low Birth Weight Neonates

PURPOSE

Spontaneous intestinal perforation (SIP) and necrotizing enterocolitis (NEC) are distinct disease processes associated with significant morbidity and mortality. Initial treatment, laparotomy (LP) versus peritoneal drainage (PD), is disease specific however it can be difficult to distinguish these diagnoses preoperatively. We investigated clinical characteristics associated with each diagnosis and constructed a scoring algorithm for accurate preoperative diagnosis.

METHODS

A cohort of extreme and very low birth weight (<1500 g) neonates surgically treated for SIP or NEC between 07/2004-09/2022 were reviewed. Clinical characteristics included gestational age (GA), birth weight (BW), feeding history, physical exam, and laboratory/radiological findings. Intraoperative diagnosis was used to determine SIP vs NEC. Pre-drain diagnosis was used for patients treated with PD only.

RESULTS

338 neonates were managed for SIP (n = 269, 79.6%) vs NEC (n = 69, 20.4%). PD was definitive treatment in 146 (43.2%) patients and 75 (22.2%) patients were treated with upfront LP. Characteristics associated with SIP included younger GA, younger age at initial laparotomy or drainage (ALD), and history of trophic or no feeds. Multivariate logistic regression determined pneumatosis, abdominal wall erythema, higher ALD and history of feeds to be highly predictive of NEC. A 0-8-point scale was designed based on these characteristics with the area under the receiver operating characteristic curve of 0.819 (95% CI 0.756-0.882) for the diagnosis of NEC. A threshold score of 1.5 had a 95.2% specificity for NEC.

CONCLUSION

Utilizing clinical characteristics associated with SIP & NEC we developed a scoring system designed to assist surgeons accurately distinguish SIP vs NEC in neonates.

TYPE OF STUDY

Retrospective Chart Review.

LEVEL OF EVIDENCE

Level III.

Necrotizing enterocolitis following spontaneous intestinal perforation in very low birth weight neonates

PURPOSE

Necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP) are severe gastrointestinal complications of prematurity. The clinical presentation and treatment of NEC and SIP (peritoneal drain vs laparotomy) can overlap; however, the pathogenesis is distinct. Therefore, a patient initially treated for SIP can subsequently develop NEC. This phenomenon has only been described in case reports, and no risk factor evaluation exists. We evaluate clinical characteristics, risk factors, and outcomes of patients treated for a distinct episode of NEC after SIP.

METHODS

We performed a retrospective review of very low birth weight (<1500 g) neonates who presented with pneumoperitoneum between 07/2004 and 09/2022. Data was obtained from two separate neonatal intensive care units that were part of the same institution. Patients with an initial preoperative, intraoperative, or pathological diagnosis of NEC were excluded. Patients with an intraoperative diagnosis of SIP or preoperative diagnosis of SIP successfully treated with a peritoneal drain (PD) were evaluated. Patients subsequently treated (medically or surgically) for NEC after SIP were then compared to SIP-alone patients. Clinical characteristics included demographics, gestational age (GA), birth weight (BW), perinatal risk factors (chorioamnionitis, steroids, indomethacin), postoperative feeding regimen, and length of stay (LOS) were compared.

RESULTS

Of the 278 patients included, 31 (11.2%) patients had NEC after SIP. There was no difference in GA (25 weeks vs 25 weeks, p = 0.933) or BW (760 g vs 735 g, p = 0.370) between NEC after SIP vs SIP alone cohorts, respectively. Twenty (64%) of NEC after-SIP patients were previously treated with LP. NEC after SIP occurred with a median onset of 56 days. Pneumatosis was the most frequent (81%) presenting symptom and 12 (39%) patients had hematochezia. Four (12.9%) patients required LP for NEC and all had NEC intraoperatively and on pathology. A majority (77.4%) of patients were on breast milk (BM) at time of NEC diagnosis. NEC after SIP patients had lower maternal age at delivery (29.0 vs 25.0, p = 0.055) and the incidence of NEC after LP (primary or failed drain) was higher than PD alone (16.7% vs 6.2%, p = 0.007). NEC after SIP patients had longer LOS (135 vs 81, p < 0.001).

CONCLUSION

We report an 11.2% incidence of NEC at a median of 56 days following successful treatment of SIP, resulting in increased LOS. SIP patients are a high-risk cohort and protocols to prevent this phenomenon should be investigated.

Administration of Adipose Tissue Derived Stem Cells before the Onset of the Disease Lowers the Levels of Inflammatory Cytokines IL-1 and IL-6 in the Rat Model of Necrotizing Enterocolitis

There is little research concerning the role of stem cells in necrotizing enterocolitis (NEC). Bone marrow-derived mesenchymal stem cells (BMDSC) and amniotic fluid-derived stem cells significantly reduced the amount and severity of NEC in the animal models. ADSCs share similar surface markers and differentiation potential with BMDSCs. Their potential role in the setting of NEC has not been researched before. The hypothesis of the study was that prophylactic intraperitoneal administration of ADSCs before the onset of the disease will result in limiting the inflammatory response, effecting a lower incidence of NEC. On a molecular level, this should result in lowering the levels of inflammatory cytokines IL-1 and IL-6. The local ethical committee for animal experiments approval was acquired (WAW2/093/2021). We utilized a self-modified rat NEC model based on single exposure to hypothermia, hypoxia, and formula feeding. One hundred and twenty-eight rat puppies were divided into two groups-prophylaxis (ADSC-NEC, n = 66) and control group (NEC-PLCB, n = 62)-to measure the influence of ADSCs administration on the inflammatory changes in NEC, the level of cell engraftment, and the histopathology of the disease. The analysis did not show a significant effect on histopathology between groups, H(2) = 2.12; p = 0.347; η²H = 0.00. The intensity of the NEC variable results was similar across the analyzed groups (NEC-PLCB and ADSC-NEC). For IL-1 and IL-6, the difference between the NEC-PLCB group and the ADSC-NEC group was statistically significant, p = 0.002 and p < 0.001, respectively. To conclude, administration of adipose tissue-derived stem cells before the onset of the disease lowers the levels of inflammatory cytokines IL-1 and IL-6 but does not affect the histopathological results in the rat model of NEC.

Does serum albumin at the onset of necrotisıng enterocolitis predict severe disease in preterm infants?

OBJECTIVE

To investigate whether laboratory markers obtained at the onset of necrotising enterocolitis (NEC) predict the severity of the disease in preterm infants.

METHODS

Prospective cohort study conducted in a tertiary referance hospital. A total of 88 preterm infants were included in the study. Of those, 60 infants had the diagnosis of severe NEC, while the remaining 28 infants constituted the non-severe NEC group. Severe NEC was defined as surgical NEC or NEC-related mortality. Infants with and without severe NEC were compared in terms of demographic, clinical and laboratory characteristics.

RESULTS

At the onset of disease, infants with severe NEC noted to have lower platelet count and serum ALB levels (p = 0.011, p = 0.004; respectively), whereas higher CRP, and serum lactate levels (p = 0.009, p = 0.008; respectively). Multiple binary logistic regression analyses showed that CRP (1.03(1.01-1.05), p = 0.024) and serum albumin level (0.16(0.04-0.64), p = 0.010) were statistically significant independent risk factors for severe NEC. The optimal cut-off value for the serum ALB level was found to be 23 g/L with 52% sensitivity (95%CI: 37-68%) and 84% specificity (95%CI: 60-97%) (AUC 0.727; p = 0.002).

CONCLUSION

Serum ALB level at NEC onset might be a reliable biomarker for severe disease in preterm infants.

An anti-eCIRP strategy for necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is a severe gastrointestinal disease characterized by intestinal inflammation and injury, with high mortality risk. Extracellular cold-inducible RNA-binding protein (eCIRP) is a recently discovered damage-associated molecular pattern that propagates inflammation and tissue injury; however, the role of eCIRP in NEC remains unknown. We hypothesize that eCIRP exacerbates NEC pathogenesis and the novel eCIRP-scavenging peptide, milk fat globule-epidermal growth factor-factor VIII (MFG-E8)-derived oligopeptide 3 (MOP3), attenuates NEC severity, serving as a new therapeutic strategy to treat NEC.

METHODS

Stool samples from premature neonates were collected prospectively and eCIRP levels were measured. Wild-type (WT) and CIRP-/- mouse pups were subjected to NEC utilizing a combination of hypoxia and hypercaloric formula orogastric gavage with lipopolysaccharide supplementation. In parallel, WT pups were treated with MOP3 or vehicle. Endpoints including NEC severity, intestinal injury, barrier dysfunction, lung injury, and overall survival were determined.

RESULTS

Stool samples from NEC neonates had elevated eCIRP levels compared to healthy age-matched controls (p < 0.05). CIRP-/- pups were significantly protected from NEC severity, intestinal injury, bowel inflammation, intestinal barrier dysfunction, lung injury, and systemic inflammation. NEC survival was 100% for CIRP-/- pups compared to 65% for WT (p < 0.05). MOP3 treatment recapitulated the benefits afforded by CIRP-knockdown, preventing NEC severity, improving inflammatory profiles, and attenuating organ injury. MOP3 treatment improved NEC survival to 80% compared to 50% for vehicle treatment (p < 0.05).

CONCLUSIONS

eCIRP exacerbates NEC evidenced by protection with CIRP-deficiency and administration of MOP3, a CIRP-directed therapeutic, in a murine model. Thus, eCIRP is a novel target with human relevance, and MOP3 is a promising treatment for lethal NEC.

Impact of postoperative necrotizing enterocolitis after neonatal cardiac surgery on neurodevelopmental outcome at 1 year of age

Objectives

We analyzed the impact of postoperative necrotizing enterocolitis (NEC) after cardiac surgery in neonatal age on neurodevelopmental (ND) outcome at 1 year of age.

Methods

Using data from the Swiss Neurodevelopmental Outcome Registry for Children with Congenital Heart Disease (ORCHID), we analyzed perioperative variables including postoperative NEC (Bell's stage ≥2) and 1-year ND outcome (Bayley III).

Results

The included patients (n = 101) had congenital heart disease (CHD), categorized as follows: 77 underwent biventricular repair for CHD with two functional chambers, 22 underwent staged palliation until the Fontan procedure for CHD with single ventricle physiology (n = 22), or 4 underwent single ventricle palliation or biventricular repair for borderline CHD (n = 4). Neonatal cardiopulmonary bypass (CBP) surgery was performed at a median age (IQR) of 8 (6) days. NEC occurred in 16 patients. Intensive care unit (ICU) length of stay (LOS) and the total duration of the hospitalization were longer in children with NEC than those in others (14 with vs. 8 days without NEC, p < 0.05; 49 with vs. 32 days without NEC, p < 0.05). The Bayley III scores of the analyzed patients determined at an age of 11.5 ± 1.5 months showed cognitive (CCS) (102.2 ± 15.0) and language scores (LCS) (93.8 ± 13.1) in the normal range and motor composite scores (MCS) (88.7 ± 15.9) in the low-normal range. After adjusting for socioeconomic status and CHD type, patients with NEC had lower CCS scores [β = -11.2 (SE 5.6), p = 0.049]. Using a cumulative risk score including NEC, we found a higher risk score to be associated with both lower CCS [β = -2.8 (SE 1.3), p = 0.030] and lower MCS [β = -3.20 (SE 1.3), p = 0.016].

Conclusions

Postoperative NEC is associated with longer ICU and hospital LOS and contributes together with other complications to impaired ND outcome at 1 year of age. In the future, national and international patient registries may provide the opportunity to analyze large cohorts and better identify the impact of modifiable perioperative risk factors on ND outcome.

Clinical Trial Registration

ClinicalTrials.gov identifier: NCT05996211.

Immunological aspects of necrotizing enterocolitis models: a review

Necrotizing enterocolitis (NEC) is one of the most devasting diseases affecting preterm neonates. However, despite a lot of research, NEC's pathogenesis remains unclear. It is known that the pathogenesis is a multifactorial process, including (1) a pathological microbiome with abnormal bacterial colonization, (2) an immature immune system, (3) enteral feeding, (3) an impairment of microcirculation, and (4) possibly ischemia-reperfusion damage to the intestine. Overall, the immaturity of the mucosal barrier and the increased expression of Toll-like receptor 4 (TLR4) within the intestinal epithelium result in an intestinal hyperinflammation reaction. Concurrently, a deficiency in counter-regulatory mediators can be seen. The sum of these processes can ultimately result in intestinal necrosis leading to very high mortality rates of the affected neonates. In the last decade no substantial advances in the treatment of NEC have been made. Thus, NEC animal models as well as in vitro models have been employed to better understand NEC's pathogenesis on a cellular and molecular level. This review will highlight the different models currently in use to study immunological aspects of NEC.

Photoacoustic imaging for non-invasive assessment of biomarkers of intestinal injury in experimental necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is an often-lethal disease of the premature infant intestinal tract, exacerbated by significant diagnostic difficulties. In NEC, the intestine exhibits hypoperfusion and dysmotility, contributing to disease pathogenesis. However, these features cannot be accurately and quantitively assessed with current imaging modalities. We have previously demonstrated the ability of photoacoustic imaging (PAI) to non-invasively assess intestinal tissue oxygenation and motility in a healthy neonatal rat model.

METHODS

In this first-in-disease application, we evaluated NEC using PAI to assess intestinal health biomarkers in an experimental model of NEC. NEC was induced in neonatal rats from birth to 4-days. Healthy breastfed (BF) and NEC rat pups were imaged at 2- and 4-days.

RESULTS

Intestinal tissue oxygen saturation was measured with PAI, and NEC pups showed significant decreases at 2- and 4-days. Ultrasound and PAI cine recordings were used to capture intestinal peristalsis and contrast agent transit within the intestine. Intestinal motility, assessed using computational intestinal deformation analysis, demonstrated significant reductions in both early and established NEC. NEC damage was confirmed with histology and dysmotility was confirmed by small intestinal transit assay.

CONCLUSION

This preclinical study presents PAI as an emerging diagnostic imaging modality for intestinal disease assessment in premature infants.

IMPACT

Necrotizing enterocolitis (NEC) is a devastating intestinal disease affecting premature infants with significant mortality. NEC presents significant clinical diagnostic difficulties, with limited diagnostic confidence complicating timely and effective interventional efforts. This study is an important foundational first-in-disease preclinical study that establishes the utility for PAI to detect changes in intestinal tissue oxygenation and intestinal motility with NEC disease induction and progression. This study demonstrates the feasibility and exceptional promise for the use of PAI to non-invasively assess oxygenation and motility in the healthy and diseased infant intestine.

Modification of Experimental Model of Necrotizing Enterocolitis (NEC) in Rat Pups by Single Exposure to Hypothermia and Hypoxia and Impact of Mother's Milk on Incidence of Disease

BACKGROUND Necrotizing enterocolitis (NEC) is a potentially life-threatening disease that affects the intestine of the neonate, causing necrosis and general inflammation. Treatment consists of feeding cessation and antibiotic therapy. In more severe cases, surgical intervention is necessary. Recently, different NEC models have been used to study the development of novel diagnostic and therapeutic methods. This work modified an experimental NEC model in rat pups by a single exposure of animals to NEC-causing factors and testing the impact of mother's milk on prevalence of the disease. MATERIAL AND METHODS Fifty rat pups were subjected to the NEC protocol, in which they were exposed to 100% nitrogen atmosphere and cold stress for set periods of time and formula feeding with exposure to mother's milk and artificial milk. Twenty-nine pups were used for control. After a set time of 72 h, bowel fragments were obtained and examined histologically by hematoxylin-eosin staining with a modified 3-grade scale. RESULTS Histological features of NEC were present in most of the samples (10/14) in the group exposed to 1 min of hypoxia (P=0.016), 10 min of cold stress (P=0.4) and formula feeding every 3 h with no mother's milk (P=0.001). In the group of 11 animals with the same stress conditions but fed mother's milk right after birth, only 1 sample of NEC was present. CONCLUSIONS The modified experimental NEC model based on formula feeding and single exposure to hypothermia and hypoxia was assessed statistically and histologically. In this model, mother's milk had a protective effect against necrotizing enterocolitis.

Necrotizing enterocolitis: current understanding of the prevention and management

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

Superior performance of biofilm versus planktonic Limosilactobacillus reuteri in protection of the intestines and brain in a piglet model of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the leading cause of gastrointestinal-related death in premature infants. Its etiology is multifactorial, with intestinal dysbiosis playing a major role. Probiotics are a logical preventative therapy for NEC, however their benefits have been inconsistent. We previously developed a novel probiotic delivery system in which planktonic (free-living) Limosilactobacillus reuteri (Lr) is incubated with biocompatible dextranomer microspheres (DM) loaded with maltose (Lr-DM-maltose) to induce biofilm formation. Here we have investigated the effects of Lr-DM-maltose in an enteral feed-only piglet model of NEC. We found a significant decrease in the incidence of Definitive NEC (D-NEC), death associated with D-NEC, and activated microglia in the brains of piglets treated with Lr-DM-maltose compared to non-treated piglets. Microbiome analyses using 16S rRNA sequencing of colonic contents revealed a significantly different microbial community composition between piglets treated with Lr-DM-maltose compared to non-treated piglets, with an increase in Lactobacillaceae and a decrease in Clostridiaceae in Lr-DM-maltose-treated piglets. Furthermore, there was a significant decrease in the incidence of D-NEC between piglets treated with Lr-DM-maltose compared to planktonic Lr. These findings validate our previous results in rodents, and support future clinical trials of Lr in its biofilm state for the prevention of NEC in premature neonates.

Photoacoustic Imaging for Non-Invasive Assessment of Physiological Biomarkers of Intestinal Injury in Experimental Necrotizing Enterocolitis

Background

Necrotizing enterocolitis (NEC) is an often-lethal disease of the premature infants' intestinal tract that is exacerbated by significant difficulties in early and accurate diagnosis. In NEC disease, the intestine often exhibits hypoperfusion and dysmotility, which contributes to advanced disease pathogenesis. However, these physiological features cannot be accurately and quantitively assessed within the current constraints of imaging modalities frequently used in the clinic (plain film X-ray and ultrasound). We have previously demonstrated the ability of photoacoustic imaging (PAI) to non-invasively and quantitively assess intestinal tissue oxygenation and motility in a healthy neonatal rat model. As a first-in-disease application, we evaluated NEC pathogenesis using PAI to assess intestinal health biomarkers in a preclinical neonatal rat experimental model of NEC.

Methods

NEC was induced in neonatal rat pups from birth to 4 days old via hypertonic formula feeding, full-body hypoxic stress, and lipopolysaccharide administration to mimic bacterial colonization. Healthy breastfed (BF) controls and NEC rat pups were imaged at 2- and 4-days old. Intestinal tissue oxygen saturation was measured with PAI imaging for oxy- and deoxyhemoglobin levels. To measure intestinal motility, ultrasound and co-registered PAI cine recordings were used to capture intestinal peristalsis motion and contrast agent (indocyanine green) transit within the intestinal lumen. Additionally, both midplane two-dimensional and volumetric three-dimensional imaging acquisitions were assessed for oxygenation and motility.

Results

NEC pups showed a significant decrease of intestinal tissue oxygenation as compared to healthy BF controls at both ages (2-days old: 55.90% +/- 3.77% vs 44.12% +/- 7.18%; 4-days old: 56.13% +/- 3.52% vs 38.86% +/- 8.33%). Intestinal motility, assessed using a computational intestinal deformation analysis, demonstrated a significant reduction in the intestinal motility index in both early (2-day) and established (4-day) NEC. Extensive NEC damage was confirmed with histology and dysmotility was confirmed by small intestinal transit assay.

Conclusions

This study presents PAI as a successful emerging diagnostic imaging modality for both intestinal tissue oxygenation and intestinal motility disease hallmarks in a rat NEC model. PAI presents enormous significance and potential for fundamentally changing current clinical paradigms for detecting and monitoring intestinal pathologies in the premature infant.

Development of a novel definitive scoring system for an enteral feed-only model of necrotizing enterocolitis in piglets

Introduction

Necrotizing enterocolitis (NEC) is a complex inflammatory disorder of the human intestine that most often occurs in premature newborns. Animal models of NEC typically use mice or rats; however, pigs have emerged as a viable alternative given their similar size, intestinal development, and physiology compared to humans. While most piglet NEC models initially administer total parenteral nutrition prior to enteral feeds, here we describe an enteral-feed only piglet model of NEC that recapitulates the microbiome abnormalities present in neonates that develop NEC and introduce a novel multifactorial definitive NEC (D-NEC) scoring system to assess disease severity.

Methods

Premature piglets were delivered via Caesarean section. Piglets in the colostrum-fed group received bovine colostrum feeds only throughout the experiment. Piglets in the formula-fed group received colostrum for the first 24 h of life, followed by Neocate Junior to induce intestinal injury. The presence of at least 3 of the following 4 criteria were required to diagnose D-NEC: (1) gross injury score ≥4 of 6; (2) histologic injury score ≥3 of 5; (3) a newly developed clinical sickness score ≥5 of 8 within the last 12 h of life; and (4) bacterial translocation to ≥2 internal organs. Quantitative reverse transcription polymerase chain reaction was performed to confirm intestinal inflammation in the small intestine and colon. 16S rRNA sequencing was performed to evaluate the intestinal microbiome.

Results

Compared to the colostrum-fed group, the formula-fed group had lower survival, higher clinical sickness scores, and more severe gross and histologic intestinal injury. There was significantly increased bacterial translocation, D-NEC, and expression of IL-1α and IL-10 in the colon of formula-fed compared to colostrum-fed piglets. Intestinal microbiome analysis of piglets with D-NEC demonstrated lower microbial diversity and increased Gammaproteobacteria and Enterobacteriaceae.

Conclusions

We have developed a clinical sickness score and a new multifactorial D-NEC scoring system to accurately evaluate an enteral feed-only piglet model of NEC. Piglets with D-NEC had microbiome changes consistent with those seen in preterm infants with NEC. This model can be used to test future novel therapies to treat and prevent this devastating disease.

Human Bone Marrow-Derived Mesenchymal Stromal Cells Reduce the Severity of Experimental Necrotizing Enterocolitis in a Concentration-Dependent Manner

Necrotizing enterocolitis (NEC) is a devastating gut disease in preterm neonates. In NEC animal models, mesenchymal stromal cells (MSCs) administration has reduced the incidence and severity of NEC. We developed and characterized a novel mouse model of NEC to evaluate the effect of human bone marrow-derived MSCs (hBM-MSCs) in tissue regeneration and epithelial gut repair. NEC was induced in C57BL/6 mouse pups at postnatal days (PND) 3-6 by (A) gavage feeding term infant formula, (B) hypoxia/hypothermia, and (C) lipopolysaccharide. Intraperitoneal injections of PBS or two hBM-MSCs doses (0.5 × 10⁶ or 1 × 10⁶) were given on PND2. At PND 6, we harvested intestine samples from all groups. The NEC group showed an incidence of NEC of 50% compared with controls (p < 0.001). Severity of bowel damage was reduced by hBM-MSCs compared to the PBS-treated NEC group in a concentration-dependent manner, with hBM-MSCs (1 × 10⁶) inducing a NEC incidence reduction of up to 0% (p < 0.001). We showed that hBM-MSCs enhanced intestinal cell survival, preserving intestinal barrier integrity and decreasing mucosal inflammation and apoptosis. In conclusion, we established a novel NEC animal model and demonstrated that hBM-MSCs administration reduced the NEC incidence and severity in a concentration-dependent manner, enhancing intestinal barrier integrity.

The Role of the Interleukin-1 Family in Complications of Prematurity

Preterm birth is a major contributor to neonatal morbidity and mortality. Complications of prematurity such as bronchopulmonary dysplasia (BPD, affecting the lung), pulmonary hypertension associated with BPD (BPD-PH, heart), white matter injury (WMI, brain), retinopathy of prematurity (ROP, eyes), necrotizing enterocolitis (NEC, gut) and sepsis are among the major causes of long-term morbidity in infants born prematurely. Though the origins are multifactorial, inflammation and in particular the imbalance of pro- and anti-inflammatory mediators is now recognized as a key driver of the pathophysiology underlying these illnesses. Here, we review the involvement of the interleukin (IL)-1 family in perinatal inflammation and its clinical implications, with a focus on the potential of these cytokines as therapeutic targets for the development of safe and effective treatments for early life inflammatory diseases.