Temporal development of necrotizing enterocolitis in the preterm pig
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ABSTRACT: Necrotizing enterocolitis (NEC), a serious gastrointestinal disease that afflicts 5-10% of preterm infants, often progresses rapidly from mild food intolerance into extensive haemorrhage, inflammation and necrosis. Events leading to NEC have remained poorly defined. Similar disease characteristics are observed in preterm pigs 24-48 h after feeding formula. Using this model, we aimed to characterize the temporal development of NEC, and describe the functional and immunological response of the preterm intestine preceding NEC. Keywords: time course
Project description:Necrotizing enterocolitis (NEC), a serious gastrointestinal disease that afflicts 5-10% of preterm infants, often progresses rapidly from mild food intolerance into extensive haemorrhage, inflammation and necrosis. Events leading to NEC have remained poorly defined. Similar disease characteristics are observed in preterm pigs 24-48 h after feeding formula. Using this model, we aimed to characterize the temporal development of NEC, and describe the functional and immunological response of the preterm intestine preceding NEC. Keywords: time course Pigs from treatment groups TPN (n=5), and 8 h (n=5) and 24 h (n=5-6) FORM and COLOS were randomly selected for microarray analysis. Equal amounts of total distal small intestinal RNA from all pigs was pooled to make the reference sample. Samples and reference pool were labelled with Oyster 550 and 650, respectively. The in-house spotted porcine oligonucleotide microarray version 4 (POM4) is a low density microarray consisting of 384 different oligonucleotide probes representing more than 200 different immune related genes and eight different array control oligonucleotides (ArrayControl; Ambion, Nærum, Denmark). The immunologically relevant 60-70mer oligonucleotide probes represent interferons and interleukins (and receptors), chemokines (and receptors), acute phase proteins, apoptosis-related factors and sequences with relevance to Toll-like receptors and their intracellular signalling pathways.
Project description:Preterm neonates are susceptible to gastrointestinal (GI) disorders such as necrotizing enterocolitis (NEC). Maternal milk, and especially colostrum, protects against NEC via growth promoting, immunomodulatory and antimicrobial factors. The fetal enteral diet, amniotic fluid (AF), contains similar bioactive components and we hypothesized that postnatal AF administration would reduce inflammatory responses and NEC in preterm neonates. Thirty preterm pigs (92% gestation) were delivered by caesarean section and fed total parental nutrition (TPN) for 48 h followed by enteral porcine colostrum (COLOS, n=7), infant formula (FORM, n=13) or formula + porcine AF (AF, n=10). Using a previously validated model of NEC in preterm pigs, we determined the structural, functional, microbiological and immunological responses to AF when administered prior to and after introduction of a suboptimal enteral formula diet. Keywords: Healthy versus inflammed tissues in relation to necrotizing enterocolitis Pigs from each treatment group (COLOS, n=4; FORM, n=6; and AF, n=7) were randomly selected for microarray analysis of frozen distal small intestine samples. The FORM group was further divided into formula-fed healthy pigs (F-HEA, n=3) and formula-fed NEC pigs (F-NEC, n=3) in order to compare sick versus healthy formula fed pigs. Equal amounts of total distal small intestinal RNA from all pigs were pooled to make the reference sample. Samples and reference pool were labelled with Oyster 550 and 650, respectively. The in-house spotted porcine oligonucleotide microarray version 4 (POM4) is a low density microarray consisting of 384 different oligonucleotide probes representing more than 200 different immune related genes.
Project description:Preterm neonates are susceptible to gastrointestinal (GI) disorders such as necrotizing enterocolitis (NEC). Maternal milk, and especially colostrum, protects against NEC via growth promoting, immunomodulatory and antimicrobial factors. The fetal enteral diet, amniotic fluid (AF), contains similar bioactive components and we hypothesized that postnatal AF administration would reduce inflammatory responses and NEC in preterm neonates. Thirty preterm pigs (92% gestation) were delivered by caesarean section and fed total parental nutrition (TPN) for 48 h followed by enteral porcine colostrum (COLOS, n=7), infant formula (FORM, n=13) or formula + porcine AF (AF, n=10). Using a previously validated model of NEC in preterm pigs, we determined the structural, functional, microbiological and immunological responses to AF when administered prior to and after introduction of a suboptimal enteral formula diet. Keywords: Healthy versus inflammed tissues in relation to necrotizing enterocolitis
Project description:Necrotizing enterocolitis (NEC) is an acute and life-threatening gastrointestinal disorder afflicting preterm infants, which is currently unpreventable. Fecal microbiota transplantation (FMT) is a promising preventative therapy, but potential bacterial infection raise concern. Removal of bacteria from donor feces may reduce this risk while maintaining the NEC-preventive effects. We aimed to assess preclinical efficacy and safety of bacteria-free fecal filtrate transfer (FFT). Using fecal material from healthy suckling piglets, we administered FMT rectally, or cognate FFT either rectally or oro-gastrically to formula-fed preterm, cesarean-delivered piglets as a model for preterm infants, We compared gut pathology and related safety parameters with saline controls, and analyzed ileal mucosal transcriptome to gauge the host e response to FMT and FFT treatments relative to control. Results showed that oro-gastric FFT prevented NEC, whereas FMT did not perform better than control. Moreover, FFT but not FMT reduced intestinal permeability, whereas FMT animals had reduced body weight increase and intestinal growth. Global gene expression of host mucosa responded to FMT but not FFT with increased and decreased bacterial and viral defense mechanisms, respectively. In conclusion, as preterm infants are extremely vulnerable to enteric bacterial infections, rational NEC-preventive strategies need incontestable safety profiles. Here we show in a clinically relevant animal model that FFT, as opposed to FMT, efficiently prevents NEC without any recognizable side effects. If translatable to preterm infants, this could lead to a change of practice and in turn a reduction in NEC burden.
Project description: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. In this animal model, variable severity of gut NEC lesions were detected in 5d-old piglets with limited clinical signs. NEC (n=20) and control piglets (CON, n=19) were analyzed for whole blood transcriptome, revealing 344 differentially expressed genes (DEGs) between NEC and CON piglets. Co-expression network analyses and qPCR suggested AOAH, FKBP5, PAK2 as three NEC-specific genes associated with severe gut lesions. These results suggest that whole blood gene expressions are affected in preterm piglets when clinical symptoms of NEC are minimal. Blood transcriptome may be a novel tool to identify early biomarkers of NEC.
Project description:Necrotizing Enterocolitis (NEC) is an inflammation causing injury to the bowel in newborns. This project uses a rodent model that mimics the intestinal pathological changes seen in NEC to study the effect of formula feeding and hypoxia on NEC development Keywords: time series, diet, hypoxia
Project description:Necrotizing Enterocolitis (NEC) is an inflammation causing injury to the bowel in newborns. This project uses a rodent model that mimics the intestinal pathological changes seen in NEC to study the effect of formula feeding and hypoxia on NEC development
Project description:Necrotizing enterocolitis (NEC) is the most common and lethal gastrointestinal disease affecting preterm infants. NEC develops suddenly and is characterized by gut barrier destruction, an inflammatory response, intestinal necrosis and multi-system organ failure. There is currently no method for early NEC detection, and the pathogenesis of NEC remains unclear.
Project description:Necrotizing enterocolitis (NEC) is an acute gut inflammatory disorder that mainly affects preterm neonates. A large proportion of NEC survivors develop neuronal deficits later in life, however the effect of early stages of NEC on the developing brain is unknown. Using preterm pigs as a NEC-sensitive animal model, we profiled the hippocampal gene expression in response to severe NEC lesions. The NEC-induced differentially expressed genes (DEGs) in the hippocampus segregated the piglets suffering from small intestinal NEC (Si-NEC) from those showing NEC lesions only in the colon (Co-NEC). Only when NEC lesions were observed in the small intestine, did piglets show reduced physical activity together with up-regulation of hippocampal genes related to inflammation and hypoxia, which was further verified by qPCR. Cluster analyses revealed key hippocampal NEC–related DEGs for Si-NEC (23 genes, including S100A8, PDK4, EDN1, IER3, Opalin, TXNIP) and Co-NEC (3 genes: GSTM3, TF, and S100A1). Both NEC phenotypes showed only two down-regulated DEGs (TMEM 167, HBB) and were devoid of any histological signs of microglia activation. Cerebrospinal fluid (CSF) from NEC-positive pigs contained elevated levels of several inflammatory proteins and in vitro exposure of immature hippocampal neurons to NEC-related CSF promoted neuritogenesis. Further in vitro experiments with neurite outgrowth indicated that VEGF, CINC-3, S100A9 and S100A8/S100A9 may play a role in NEC effects on hippocampal development. In conclusion, NEC lesions, especially when involving the small intestine, alter hippocampal gene expression with potential neuroinflammation and effects on neural circuit formation. Our results demonstrated that gut lesions affect the immature brain at early stages of disease progression. Thus, supportive care is important for preterm infants experienced with NEC to lessen possible later neurological dysfunctions.
Project description:Major risk factors for necrotizing enterocolitis (NEC) are formula feeding and prematurity, however, their pathogenic mechanisms are unknown. We found that insufficient arginine/nitric oxide synthesis limits blood flow in the intestinal microvasculature, leading to hypoxia, mucosa damage and NEC in the premature intestine after formula feeding. Formula feeding led to increased intestinal hypoxia in pups at postnatal day 1(P1) and P5, but not in more mature pups at P9. Accordingly, blood flow in the intestinal microvasculature increased after formula feeding only in P9 pups. mRNA profiling revealed that regulators of arginine/nitric oxide synthesis are at higher levels in endothelial cells of the intestine of P9 than P1 pups. Importantly, arginine supplementation increased intestinal microvasculature blood flow, and prevented NEC, whereas an arginine antagonist exacerbated NEC. Our results suggest that balancing intestinal oxygen demand and supply in the premature intestine by modulating arginine/nitric oxide could be used to prevent NEC.