Transcriptomic analysis of the effect of remote ischaemic conditioning in an animal model of necrotising enterocolitis.

Necrotising enterocolitis (NEC) has a complex pathophysiology but the common end-point is ischaemia reperfusion injury (IRI) and intestinal necrosis. We have previously reported that RIC significantly reduces the intestinal injury in a rat model of NEC. Here we describe the changes in intestinal mRNA occurring in the intestine of animals exposed to IRI, both with and without RIC. Related rat-pups were randomly assigned to four groups: SHAM, IRI only, RIC only and RIC + IRI. IRI animals, underwent 40 min of intestinal ischaemia, and 90 min of reperfusion. Animals that underwent RIC had three cycles of 5 min of alternating ischaemia/reperfusion by means of a ligature applied to the hind limb. Samples from the terminal ileum were immediately stored in RNA-preserving media for later next generation sequencing and transciptome analysis using R v 3.6.1. Differential expression testing showed that 868 genes differentially expressed in animals exposed to RIC alone compared to SHAM and 135 in the IRI and RIC group compared to IRI alone. Comparison between these two sets showed that 25 genes were differentially expressed in both groups. Pro-inflammatory molecules: NF-ĸß2, Cxcl1, SOD2 and Map3k8 all show reduced expression in response to RIC. Targeted gene analysis revealed increased expression in PI3K which is part of the so-called RISK-pathway which is a key part of the protective mechanisms of RIC in the heart. Overall, this transcriptomic analysis shows that RIC provides a protective effect to the intestine via anti-inflammatory pathways. This could be particularly relevant to treating and preventing NEC.

MiRNA-192-5p-targeted activated leukocyte cell adhesion molecule improved inflammatory injury of neonatal necrotizing enterocolitis.

BACKGROUND: Neonatal necrotizing enterocolitis (NEC) is a common gastrointestinal emergency in neonates. MiRNA-192-5p was found associated with ulcerative colitis (UC) progression, also with aberrant expression in intestinal cancer tissue. However, the effects of miRNA-192-5p on NEC have not been reported. METHODS: Based on the bioinformatics analysis of the GEO dataset, miR-192-5p was identified as the differentially expressed miRNA in NEC, and activated leukocyte cell adhesion molecule (ALCAM) was predicted as its target. After that, in vitro, rat intestinal epithelial cell-6 (IEC-6) were stimulated with LPS to construct a cell model of NEC. IEC-6 cells were transfected with miRNA-192-5p mimics, miRNA-192-5p inhibitors, or miRNA-192-5p inhibitors + sh-ALCAM, and relevant negative control. In vivo, SD rats were treated with artificial feeding, hypoxic reoxygenation, cold stimulation, and LPS gavage to induce NEC, followed by injection of agomiR-NC or agomiRNA-192-5p. Then effects of miRNA-192-5p on NEC model IEC-6 cell viability, apoptosis, ALCAM expression, Interleukin (IL)-1ß and IL-6 levels, intestinal injury, intestinal permeability were detected. RESULTS: MiRNA-192-5p expression was downregulated in NEC IEC-6 cells, whose overexpression increased IEC-6 cell viability. MiRNA-192-5p inhibitors increased IL-1ß, IL-6 levels and promoted IEC-6 cell apoptosis. MiRNA-192-5p targeting of ALCAM decreased ALCAM expression, IL-1ß, and IL-6 levels. AgomiRNA-192-5p decreased ALCAM, IL-1ß, and IL-6 levels in intestinal tissue and pathological damage and increased miRNA-192-5p levels. CONCLUSION: MiR-192-5p protects against intestinal injury by inhibiting ALCAM-mediated inflammation and intestinal epithelial cells, which would provide a new idea for NEC treatment.

DNA methylation in necrotizing enterocolitis.

Epigenetic modifications, such as DNA methylation, are enzymatically regulated processes that directly impact gene expression patterns. In early life, they are central to developmental programming and have also been implicated in regulating inflammatory responses. Research into the role of epigenetics in neonatal health is limited, but there is a growing body of literature related to the role of DNA methylation patterns and diseases of prematurity, such as the intestinal disease necrotizing enterocolitis (NEC). NEC is a severe intestinal inflammatory disease, but the key factors that precede disease development remain to be determined. This knowledge gap has led to a failure to design effective targeted therapies and identify specific biomarkers of disease. Recent literature has identified altered DNA methylation patterns in the stool and intestinal tissue of neonates with NEC. These findings provide the foundation for a new avenue in NEC research. In this review, we will provide a general overview of DNA methylation and then specifically discuss the recent literature related to methylation patterns in neonates with NEC. We will also discuss how DNA methylation is used as a biomarker for other disease states and how, with further research, methylation patterns may serve as potential biomarkers for NEC.

Blocking OLFM4/galectin-3 axis in placental polymorphonuclear myeloid-derived suppressor cells triggers intestinal inflammation in newborns.

Fetal growth restriction (FGR) is a major cause of premature and low-weight births, which increases the risk of necrotizing enterocolitis (NEC); however, the association remains unclear. We report a close correlation between placental polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) and NEC. Newborns with previous FGR exhibited intestinal inflammation and more severe NEC symptoms than healthy newborns. Placental PMN-MDSCs are vital regulators of fetal development and neonatal gut inflammation. Placental single-cell transcriptomics revealed that PMN-MDSCs populations and olfactomedin-4 gene (Olfm4) expression levels were significantly increased in PMN-MDSCs in later pregnancy compared to those in early pregnancy and non-pregnant females. Female mice lacking Olfm4 in myeloid cells mated with wild-type males showed FGR during pregnancy, with a decreased placental PMN-MDSCs population and expression of growth-promoting factors (GPFs) from placental PMN-MDSCs. Galectin-3 (Gal-3) stimulated the OLFM4-mediated secretion of GPFs by placental PMN-MDSCs. Moreover, GPF regulation via OLFM4 in placental PMN-MDSCs was mediated via hypoxia inducible factor-1α (HIF-1α). Notably, the offspring of mothers lacking Olfm4 exhibited intestinal inflammation and were susceptible to NEC. Additionally, OLFM4 expression decreased in placental PMN-MDSCs from pregnancies with FGR and was negatively correlated with neonatal morbidity. These results revealed that placental PMN-MDSCs contributed to fetal development and ameliorate newborn intestinal inflammation.

Values of serum intestinal fatty acid-binding protein, fecal calprotectin, and fecal human ß-defensin 2 for predicting necrotizing enterocolitis.

BACKGROUND: This study aimed to assess the diagnostic potential of serum intestinal fatty acid-binding protein (I-FABP), fecal calprotectin (FC), and fecal human ß-defensin 2 (hBD2) in predicting necrotizing enterocolitis (NEC) in preterm infants. METHODS: A prospective cohort of neonates with a gestational age < 32 weeks, suspected of NEC, was enrolled between June 2021 and December 2022. Serum I-FABP, FC, and fecal hBD2 levels were measured upon NEC suspicion, and diagnosis was confirmed through radiological examination or surgical intervention. Diagnostic precision of serum I-FABP, FC, and fecal hBD2 was assessed using a logistic regression model with multiple variables. RESULTS: The study included 70 neonates (45 males, 25 females), with 30 developing NEC (40% Stage III, n = 12; 60% Stage II, n = 18) and 40 in the control group. NEC patients exhibited significantly higher serum I-FABP and FC levels (4.76 ng/mL and 521.56 µg/g feces, respectively) than those with other diagnoses (1.38 ng/mL and 213.34 µg/g feces, respectively; p ˂ 0.05 for both biomarkers). Stage II NEC neonates showed elevated fecal hBD2 levels (376.44 ng/g feces) than Stage III NEC neonates and controls (336.87 ng/g and 339.86 ng/g feces, respectively; p ˂ 0.05). No such increase was observed in infants progressing to Stage III NEC. Using a serum I-FABP threshold of > 2.54 ng/mL yielded 76.7% sensitivity, 87.5% specificity, 82.1% positive predictive value (PPV), and 83.3% negative predictive value (NPV). For FC (cutoff > 428.99 µg/g feces), corresponding values were 76.7% sensitivity, 67.5% specificity, 63.9% PPV, and 79.4% NPV. CONCLUSION: Serum I-FABP and FC levels are valuable for early NEC detection and provide insights into disease severity. Low fecal hBD2 levels suggest an inadequate response to luminal bacteria, potentially rendering these infants more susceptible to NEC development or exacerbation.

miR-375-3p targets YWHAB to attenuate intestine injury in neonatal necrotizing enterocolitis.

PURPOSE: Necrotizing enterocolitis (NEC) is a significant contributor to neonatal mortality. This study aimed to investigate the role of high levels of miR-375-3p in breast milk in the development of NEC and elucidate its mechanism. METHODS: Differential expression of miR-375-3p in the intestines of breast-fed and formula-fed mice was confirmed using real-time polymerase chain reaction (RT-PCR). NEC mice models were established, and intestinal injury was assessed using HE staining. RT-PCR and Western blot were conducted to examine the expression of miR-375-3p, tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein ß (YWHAB), as well as the inflammatory in IEC-6 cells, and intestinal tissues obtained from NEC mice and patients. Flow cytometry and cell counting kit-8 (CCK-8) were employed to elucidate the impact of miR-375-3p and YWHAB on cell apoptosis and proliferation. RESULTS: Breastfeeding increases miR-375-3p expression in the intestines. The expression of miR-375-3p in NEC intestinal tissues exhibited a significant decrease compared to the healthy group. Additionally, the expression of interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α) was higher in the NEC group compared to the control group. Down-regulation of miR-375-3p inhibited IEC-6 cell proliferation, increased apoptosis, and elevated secretion of inflammatory factors. Bioinformatics revealed that YWHAB may be a target of miR-375-3p. RT-PCR and Western blot indicated a down-regulation of YWHAB expression in intestines of NEC patients and mice. Furthermore, YWHAB was found to be positively connected with miR-375-3p. Knockdown miR-375-3p down-regulated YWHAB expression in cells. Inhibition of YWHAB exhibited similar effects to miR-375-3p in IEC-6 cells. YWHAB plasmid partially reverse cellular functional impairment induced by miR-375-3p knockdown. CONCLUSIONS: Breastfeeding elevated miR-375-3p expression in intestines in neonatal mice. MiR-375-3p leads to a decrease in apoptosis of intestinal epithelial cells, an increase in cell proliferation, and a concomitant reduction in the expression of inflammatory factors partly through targeting YWHAB.

Melatonin alleviates necrotizing enterocolitis by reducing bile acid levels through the SIRT1/FXR signalling axis.

Bile acids (BAs) have increasingly been implicated in the onset and progression of necrotizing enterocolitis (NEC); multiple findings have demonstrated their ability to induce damage to the intestinal epithelium, thereby exacerbating disease severity. Although we previously showed that melatonin was able to treat NEC by correcting the Treg/Th17 imbalance, the modulatory effect of melatonin on BAs remains unclear. In this study, we conducted transcriptome analysis on intestinal tissues from patients with NEC and validated these findings. Subsequently, we treated mice with melatonin alone or in combination with an agonist/inhibitor of Sirtuin 1 (SIRT1) to assess faecal and serum BA levels, the expression levels of BA transporters and regulators, and the extent of intestinal injury. Our transcriptome results indicated dysregulation of BA metabolism and abnormal expression of BA transporters in patients with NEC, which were also observed in our NEC mouse model. Furthermore, exogenous BAs were found to aggravate NEC severity in mice. Notably, melatonin effectively restored the aberrant expression of BA transporters, such as apical membrane sodium-dependent bile acid transporters (ASBT), ileal bile acid-binding protein (IBABP), and organic solute transporter-alpha (OST-α), by upregulating SIRT1 expression while reducing farnesoid X receptor (FXR) acetylation, consequently leading to decreased serum and faecal BA levels and mitigated NEC severity. Thus, we propose a potential mechanism through which melatonin reduces BA levels via the SIRT1/FXR signalling axis in an NEC mouse model. Collectively, these results highlight that melatonin holds promise for reducing BA levels and represents a promising therapeutic strategy for treating NEC.

Potential role of bile acids in the pathogenesis of necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) is one of the most common acute gastrointestinal diseases in preterm infants. Recent studies have found that NEC is not only caused by changes in the intestinal environment but also by the failure of multiple systems and organs, including the liver. The accumulation of bile acids (BAs) in the ileum and the disorder of ileal BA transporters are related to the ileum injury of NEC. Inflammatory factors such as tumor necrosis factor (TNF)-α and interleukin (IL)-18 secreted by NEC also play an important role in regulating intrahepatic BA transporters. As an important link connecting the liver and intestinal circulation, the bile acid metabolic pathway plays an important role in the regulation of intestinal microbiota, cell proliferation, and barrier protection. In this review, we focus on how bile acids explore the dynamic changes of bile acid metabolism in necrotizing enterocolitis and the potential therapeutic value of targeting the bile acid signaling pathways.

Clostridium scindens exacerbates experimental necrotizing enterocolitis via upregulation of the apical sodium-dependent bile acid transporter.

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in premature infants. Evidence indicates that bile acid homeostasis is disrupted during NEC: ileal bile acid levels are elevated in animals with experimental NEC, as is expression of the apical sodium-dependent bile acid transporter (Asbt). In addition, bile acids, which are synthesized in the liver, are extensively modified by the gut microbiome, including via the conversion of primary bile acids to more cytotoxic secondary forms. We hypothesized that the addition of bile acid-modifying bacteria would increase susceptibility to NEC in a neonatal rat model of the disease. The secondary bile acid-producing species Clostridium scindens exacerbated both incidence and severity of NEC. C. scindens upregulated the bile acid transporter Asbt and increased levels of intraenterocyte bile acids. Treatment with C. scindens also altered bile acid profiles and increased hydrophobicity of the ileal intracellular bile acid pool. The ability of C. scindens to enhance NEC requires bile acids, as pharmacological sequestration of ileal bile acids protects animals from developing disease. These findings indicate that bile acid-modifying bacteria can contribute to NEC pathology and provide additional evidence for the role of bile acids in the pathophysiology of experimental NEC.NEW & NOTEWORTHY Necrotizing enterocolitis (NEC), a life-threatening gastrointestinal emergency in premature infants, is characterized by dysregulation of bile acid homeostasis. We demonstrate that administering the secondary bile acid-producing bacterium Clostridium scindens enhances NEC in a neonatal rat model of the disease. C. scindens-enhanced NEC is dependent on bile acids and driven by upregulation of the ileal bile acid transporter Asbt. This is the first report of bile acid-modifying bacteria exacerbating experimental NEC pathology.

Identification and evaluation of probiotic potential of Bifidobacterium breve AHC3 isolated from chicken intestines and its effect on necrotizing enterocolitis (NEC) in newborn SD rats.

Necrotizing enterocolitis (NEC) is a severe intestinal disease of the newborn infants, associated with high morbidity and mortality. It has been reported that Bifidobacterium could protect the intestinal barrier function and reduce the risk of NEC. This study aimed to evaluate the probiotic potential of Bifidobacterium strains isolated from the chicken intestines and its effect on necrotizing enterocolitis in newborn SD rats. Out of 32 isolates, B. breve AHC3 not only exhibited excellent probiotic potential, including tolerance to artificial simulated gastric conditions, adhesion to HT-29 cells, antioxidant capacity and antibacterial activity, but also possessed reliable safety. Additionally, NEC model was established to further investigate the effect of B. breve AHC3 on necrotizing enterocolitis in newborn SD rats. It was illustrated that administration of B. breve AHC3 significantly not only reduced the incidence of NEC (from 81.25% to 34.38%) (P< 0.05), but also alleviated the severity of ileal injury (P< 0.05). Compared with NEC model, B. breve AHC3 could significantly decrease the level of proinflammatory factor TNF-α (P< 0.05) and increase the level of antiinflammatory factor IL-10 (P< 0.05) in the ileum of NEC rats. Through the intervention of B. breve AHC3, the gray value of inducible nitric oxide synthase (iNOS) in intestinal tissue of NEC rats was significantly reduced (P< 0.05). It was indicated that B. breve AHC3 exhibited prominent probiotic potential and reliable safety. In the neonatal SD rat model of NEC, B. breve AHC3 had an available protective effect on the intestinal injury of NEC, which might be related to reducing the inflammatory reaction in the ileum and inhibiting the expression of iNOS in intestinal tissue cells. B. breve AHC3 could be used as a potential treatment for human NEC.

miRNA-301 As a molecule promoting necrotizing enterocolitis by inducing inflammation.

OBJECTIVE: Necrotizing enterocolitis (NEC) is a devastating inflammatory disease with high morbidity and mortality, mainly affecting premature infants. This study aimed to explore the role of miRNA-301a in the pathogenesis of NEC. METHODS: The differentially expressed miRNAs and mRNAs were screened by collating RNA-Seq data from the GEO database of intestinal tissue samples. The differential miRNA-mRNAs regulatory network was constructed based on functional enrichment analysis. Newborn BALB/c mice were used to establish the NEC model. Haematoxylin and eosin staining was used to assess intestinal damage. The levels of IL-8 and TNF-α in mouse serum were evaluated by ELISA. qRT-PCR was used to detect the expression of miRNA-301a in intestinal tissues. RESULTS: Bioinformatics analysis showed that miRNA-301a was involved in intestinal lesions. Intestinal tissue damage was reduced and serum levels of the inflammatory cytokines IL-8 and TNF-α were lower in NEC model mice treated with miRNA-301a antagonists. The level of miRNA-301a in intestinal tissues of NEC model mice was significantly higher than in the control group and miRNA-301a antagonists treated group. CONCLUSION: miRNA-301a plays an important role in the pathogenesis of NEC by promoting inflammation, and is a potential therapeutic target of NEC.

Research Models to Mimic Necrotizing Enterocolitis and Inflammatory Bowel Diseases: Focus on Extracellular Vesicles Action.

This review focuses on the crucial role of the intestinal epithelium in maintaining intestinal homeostasis and its significance in the pathogenesis of necrotizing enterocolitis (NEC) and inflammatory bowel diseases (IBD). NEC is a devastating neonatal disease, while IBD represents a global healthcare problem with increasing incidence. The breakdown of the intestinal barrier in neonates is considered pivotal in the development and progression of both disorders. This review provides an overview of the current state of in vitro, ex vivo, and animal models to study epithelial injury in NEC and IBD, addressing pertinent questions that engage clinicians and researchers alike. Despite significant advancements in early recognition and aggressive treatment, no single therapy has been conclusively proven effective in reducing the severity of these disorders. Although early interventions have improved clinical outcomes, NEC and IBD continue to impose substantial morbidity, mortality, and economic burdens on affected individuals and society. Consequently, exploring alternative therapeutic options capable of preventing and treating the sequelae of NEC and IBD has become a pressing necessity. In recent decades, extracellular vehicles (EVs) have emerged as a potential solution to modulate the pathogenic mechanism in these multifactorial and complex disorders. Despite the diverse array of proposed models, a comprehensive model to investigate and decelerate the progression of NEC and IBD remains to be established. To bridge the translational gap between preclinical studies and clinical applications, enhancements in the technical development of gut-on-a-chip models and EVs hold considerable promise.

Astragaloside IV regulates TL1A and NF-κB signal pathway to affect inflammation in necrotizing enterocolitis.

AIM: This study aims to explore the possible effect of Astragaloside IV (AS-IV) on necrotizing enterocolitis (NEC) neonatal rat models and verify the possible implication of TNF-like ligand 1 A (TL1A) and NF-κB signal pathway. METHODS: NEC neonatal rat models were established through formula feeding, cold/asphyxia stress and Lipopolysaccharide (LPS) gavage method. The appearance, activity and skin as well as the pathological status of rats subjected to NEC modeling were assessed. The intestinal tissues were observed after H&E staining. The expression of oxidative stress biomarkers (SOD, MDA and GSH-Px) and inflammatory cytokines (TNF-α, IL-1ß and IL-6) were detected by ELISA and qRT-PCR. Western blotting and immunohistochemistry were applied to detect expressions of TL1A and NF-κB signal pathway-related proteins. Cell apoptosis was assessed by TUNEL. RESULTS: NEC neonatal rat models were established successfully, in which TL1A was highly expressed and NF-κB signal pathway was activated, while TL1A and NF-κB signal pathway can be suppressed by AS-IV treatment in NEC rats. Meanwhile, inflammatory response in intestinal tissues was increased in NEC rat models and AS-IV can attenuate inflammatory response in NEC rats through inhibiting TL1A and NF-κb signal pathway. CONCLUSION: AS-IV can inhibit TL1A expression and NF-κb signal pathway to attenuate the inflammatory response in NEC neonatal rat models.

Persistent Proclivity to a Proinflammatory State in a Human Enteroid Model of Necrotizing Enterocolitis.

Background: Necrotizing enterocolitis (NEC) is a devastating disease of premature neonates with substantial morbidity and mortality. Necrotizing enterocolitis is associated with prematurity, a hyperinflammatory response, and dysregulation of intestinal barrier function. We hypothesize that patients with NEC will have an increased hyperinflammatory intestinal response compared with those without NEC. Patients and Methods: Enteroids were generated from intestinal tissue from neonates undergoing resection. They were treated with 100 mcg/mL lipopolysaccharide (LPS), subjected to 24 hours of hypoxia inducing experimental NEC, then compared with untreated controls. Expression of tumor necrosis factor (TNF-α) and interleukin 8 (IL-8) were evaluated via reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) to measure inflammatory response. Analysis of variance (ANOVA) determined statistical significance (p < 0.05). Results: Treated NEC-derived enteroids expressed significantly higher levels of IL-8 (RT-qPCR, p = 0.003; ELISA, p = 0.0002) compared with untreated NEC-derived enteroids with an increase in inflammatory marker concentration in those with a greater degree of prematurity (ELISA, p = 0.0015). A higher level of IL-8 was seen in NEC-derived enteroids compared with control after treatment (RT-qPCR, p = 0.024). Tumor necrosis factor-α levels were elevated in treated NEC-derived enteroids compared with untreated NEC-derived enteroids (RT-qPCR, p = 0.006; ELISA, p = 0.002) and compared with treated non-NEC-derived enteroids (RT-qPCR, p = 0.025; ELISA, p < 0.0001). Conclusions: Enteroids generated from neonates with NEC have an elevated hyperinflammatory response in response to NEC-inducing stimuli compared with controls. Enteroids generated from neonates with NEC with a greater degree of prematurity have a larger increase in inflammatory markers. This tendency toward a hyperinflammatory state may be correlated with an infant's proclivity to develop NEC and further demonstrates the hyperinflammatory state of prematurity.

Bovine milk-derived exosomes attenuate NLRP3 inflammasome and NF-κB signaling in the lung during neonatal necrotizing enterocolitis.

PURPOSE: Necrotizing enterocolitis (NEC), an inflammatory intestinal disease common in premature infants, has been associated with the development of lung damage. Toll-like receptor 4 has been shown to regulate inflammation in the NEC lungs, however, other important inflammatory mechanisms have not been thoroughly investigated. In addition, we reported that milk-derived exosomes were able to attenuate intestinal injury and inflammation in experimental NEC. This study aims to (i) investigate the role of the NLRP3 inflammasome and NF-κB pathway in regulating lung damage during experimental NEC; and (ii) evaluate the therapeutic potential of bovine milk exosomes in reducing lung inflammation and injury during NEC. METHODS: NEC was induced by gavage feeding of hyperosmolar formula, hypoxia, and lipopolysaccharide administration in neonatal mice from postnatal days 5-9. Exosomes were obtained by ultracentrifugation of bovine milk and administered during each formula feed. RESULTS: The lung of NEC pups showed increased inflammation, tissue damage, NLRP3 inflammasome expression, and NF-κB pathway activation, which were attenuated upon exosome administration. CONCLUSION: Our findings suggest that the lung undergoes significant inflammation and injury following experimental NEC which are attenuated by bovine milk-derived exosomes. This emphasizes the therapeutic potential of exosomes not just on the intestine but also on the lung.

NAMPT inhibition relieves intestinal inflammation by regulating macrophage activation in experimental necrotizing enterocolitis.

Nicotinamide phosphoribosyl transferase (NAMPT) is associated with various NAD+ -consuming enzymatic reactions. The precise role in intestinal mucosal immunity in necrotizing enterocolitis (NEC) is not well defined. Here, we examined whether NAMPT inhibition by the highly specific inhibitor FK866 could alleviate intestinal inflammation during the pathogenesis of NEC. In the present study, we showed that NAMPT expression was upregulated in the human terminal ileum of human infants with NEC. FK866 administration attenuated M1 macrophage polarization and relieved the symptoms of experimental NEC pups. FK866 inhibited intercellular NAD+ levels, macrophage M1 polarization, and the expression of NAD+ -dependent enzymes, such as poly (ADP ribose) polymerase 1 (PARP1) and Sirt6. Consistently, the capacity of macrophages to phagocytose zymosan particles, as well as antibacterial activity, were impaired by FK866, whereas NMN supplementation to restore NAD+ levels reversed the changes in phagocytosis and antibacterial activity. In conclusion, FK866 reduced intestinal macrophage infiltration and skewed macrophage polarization, which is implicated in intestinal mucosal immunity, thereby promoting the survival of NEC pups.

PRELIMINARY FINDINGS OF TLR2 AND TLR4 EXPRESSION IN PRETERM NEONATES WITH NECROTIZING ENTEROCOLITIS.

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in preterm infants. Despite significant advances made in the prevention and treatment of disease so far, there has not been much change in the rate of mortality and morbidity associated with NEC. Although the factors affecting the development of necrotizing enterocolitis are not yet known precisely, prematurity is thought to be the most important risk factor for the development of NEC. This study aims to determine toll-like receptor (TLR) 2 and TLR4 expression levels in preterm neonates. A total of 50 preterm infants (patient: 42, control: 8) were included in the study. TLR2 and TLR4 expression levels were analysed by the RT-qPCR method. While there was no difference in infants' birth weight (g), gestational age (months), mother's age (years), father's age (years), and WBC (109/L); HGB (g/dL) and RBC (1012/L) were found to be significantly higher in the group with NEC (p<0.05). When TLR2 and TLR4 relative gene expression levels of neonates were evaluated (log2), it was determined that there was a significant difference between the two groups (below 1500 g) (p<0.001). TLR4 relative expression (2^-ddCt, above 1500 g) was higher in the NEC group than in the healthy group, while TLR2 relative expression (2^-ddCt, above 1500 g) was higher in the healthy group. TLR2 and TLR4 have been shown to have prominent roles in the development of NEC in experimental animal models and it would be significant to support this with human studies/animal models for a better understanding of the disease. Thus, it is recommended that future studies be carried out on experimental models that better replicate the human body, and dietary factors should be examined in detail.

The Impact of Maternal Probiotics on Intestinal Vitamin D Receptor Expression in Early Life.

Vitamin D signaling via the Vitamin D Receptor (VDR) has been shown to protect against intestinal inflammation. Previous studies have also reported the mutual interactions of intestinal VDR and the microbiome, indicating a potential role of probiotics in modulating VDR expression. In preterm infants, although probiotics have been shown to reduce the incidence of necrotizing enterocolitis (NEC), they are not currently recommended by the FDA due to potential risks in this population. No previous studies have delved into the effect of maternally administered probiotics on intestinal VDR expression in early life. Using an infancy mouse model, we found that young mice exposed to maternally administered probiotics (SPF/LB) maintained higher colonic VDR expression than our unexposed mice (SPF) in the face of a systemic inflammatory stimulus. These findings indicate a potential role for microbiome-modulating therapies in preventing diseases such as NEC through the enhancement of VDR signaling.

Dedifferentiated fat cells administration ameliorates abnormal expressions of fatty acids metabolism-related protein expressions and intestinal tissue damage in experimental necrotizing enterocolitis.

Neonatal necrotizing enterocolitis (NEC) is a serious disease of premature infants that necessitates intensive care and frequently results in life-threatening complications and high mortality. Dedifferentiated fat cells (DFATs) are mesenchymal stem cell-like cells derived from mature adipocytes. DFATs were intraperitoneally administrated to a rat NEC model, and the treatment effect and its mechanism were evaluated. The NEC model was created using rat pups hand fed with artificial milk, exposed to asphyxia and cold stress, and given oral lipopolysaccharides after cesarean section. The pups were sacrificed 96 h after birth for macroscopic histological examination and proteomics analysis. DFATs administration significantly improved the survival rate from 25.0 (vehicle group) to 60.6% (DFAT group) and revealed a significant reduction in macroscopical, histological, and apoptosis evaluation compared with the vehicle group. Additionally, the expression of C-C motif ligand 2 was significantly decreased, and that of interleukin-6 decreased in the DFAT group. DFAT administration ameliorated 93 proteins mainly related to proteins of fatty acid metabolism of the 436 proteins up-/down-regulated by NEC. DFATs improved mortality and restored damaged intestinal tissues in NEC, possibly by improving the abnormal expression of fatty acid-related proteins and reducing inflammation.

Intestine and brain TLR-4 modulation following N-acetyl-cysteine treatment in NEC rodent model.

Necrotizing enterocolitis (NEC) brain injury is mediated through Toll-like receptor 4 (TLR4) on the intestinal epithelium and brain microglia. Our aim was to determine whether postnatal and/or prenatal NAC can modify NEC associated intestinal and brain TLR4 expression and brain glutathione levels in a rat model of NEC. Newborn Sprague-Dawley rats were randomized into three groups: Control (n = 33); NEC (n = 32)-hypoxia and formula feeding; and NEC-NAC (n = 34)-received NAC (300 mg/kg IP) in addition to NEC conditions. Two additional groups included pups of dams treated once daily with NAC (300 mg/kg IV) for the last 3 days of pregnancy: NAC-NEC (n = 33) or NAC-NEC-NAC (n = 36) with additional postnatal NAC. Pups were sacrificed on the fifth day, and ileum and brains harvested for TLR-4 and glutathione protein levels. Brain and ileum TLR-4 protein levels were significantly increased in NEC offspring as compared to control (brain 2.5 ± 0.6 vs. 0.88 ± 0.12 U and ileum 0.24 ± 0.04 vs. 0.09 ± 0.01, p < 0.05). When NAC was administered only to dams (NAC-NEC) a significant decrease in TLR-4 levels was demonstrated in both offspring brain (1.53 ± 0.41 vs. 2.5 ± 0.6 U, p < 0.05) and ileum (0.12 ± 0.03 vs. 0.24 ± 0.04 U, p < 0.05) as compared to NEC. The same pattern was demonstrated when NAC was administered only or postnatally. The decrease in brain and ileum glutathione levels observed in NEC offspring was reversed with all NAC treatment groups. NAC reverses the increase in ileum and brain TLR-4 levels and the decrease in brain and ileum glutathione levels associated with NEC in a rat model, and thus may protect from NEC associated brain injury.