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: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:BackgroundNecrotizing enterocolitis (NEC) is an acute gut inflammatory disorder that occurs in preterm infants in the first weeks after birth. Infants surviving NEC often show impaired neurodevelopment. The mechanisms linking NEC lesions with later neurodevelopment are poorly understood but may include proinflammatory signaling in the immature brain. Using preterm pigs as a model for preterm infants, we hypothesized that severe intestinal NEC lesions are associated with acute effects on the developing hippocampus.MethodsCesarean-delivered preterm pigs (n = 117) were reared for 8 days and spontaneously developed variable severity of NEC lesions. Neonatal arousal, physical activity, and in vitro neuritogenic effects of cerebrospinal fluid (CSF) were investigated in pigs showing NEC lesions in the colon (Co-NEC) or in the small intestine (Si-NEC). Hippocampal transcriptome analysis and qPCR were used to assess gene expressions and their relation to biological processes, including neuroinflammation, and neural plasticity. Microglia activation was quantified by stereology. The neuritogenic response to selected proteins was investigated in primary cultures of hippocampal neurons.ResultsNEC development rapidly reduced the physical activity of pigs, especially when lesions occurred in the small intestine. Si-NEC and Co-NEC were associated with 27 and 12 hippocampal differentially expressed genes (DEGs), respectively. These included genes related to neuroinflammation (i.e., S100A8, S100A9, IL8, IL6, MMP8, SAA, TAGLN2) and hypoxia (i.e., PDK4, IER3, TXNIP, AGER), and they were all upregulated in Si-NEC pigs. Genes related to protection against oxidative stress (HBB, ALAS2) and oligodendrocytes (OPALIN) were downregulated in Si-NEC pigs. CSF collected from NEC pigs promoted neurite outgrowth in vitro, and the S100A9 and S100A8/S100A9 proteins may mediate the neuritogenic effects of NEC-related CSF on hippocampal neurons. NEC lesions did not affect total microglial cell number but markedly increased the proportion of Iba1-positive amoeboid microglial cells.ConclusionsNEC lesions, especially when present in the small intestine, are associated with changes to hippocampal gene expression that potentially mediate neuroinflammation and disturbed neural circuit formation via enhanced neuronal differentiation. Early brain-protective interventions may be critical for preterm infants affected by intestinal NEC lesions to reduce their later neurological dysfunctions.
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), 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:Few studies have examined the possible pregnancy-related risk factors for necrotizing enterocolitis (NEC)-associated deaths during infancy. Infant death due to NEC in preterm babies was identified from the US Linked Livebirth and Infant Death records between 2000 and 2004. The average number of cigarettes per day reported by the mothers who were smoking during pregnancy was classified in three categories: non-smoking, light smoking (<10 cigarettes/day) and heavy smoking (≥10 cigarettes/day). Logistic regression analyses examined the association between prenatal smoking and NEC-associated infant mortality rates with adjustment for potential confounders. Compared with non-smoking mothers, light and heavy smoking mothers have a higher risk of NEC-associated infant mortality [light smoking: adjusted odds ratio (aOR) = 1.21, 95% confidence interval (CI), 1.03-1.43; heavy smoking: aOR = 1.30, 95% CI, 1.12-1.52], respectively. Moreover, the association was stronger among white race (light smoking: aOR = 1.69, 95% CI, 1.34-2.13; heavy smoking: aOR = 1.44, 95% CI, 1.18-1.75) and female babies (light smoking: aOR = 1.31, 95% CI, 1.02-1.69; heavy smoking: aOR = 1.62, 95% CI, 1.29-2.02). Maternal smoking during pregnancy is associated with increased risks of infant mortality due to NEC in preterm babies, especially in white race and female babies.
Project description:Limited evidence exists to support the withholding of feeds during packed red blood cell (PRBC) transfusion to reduce the incidence of transfusion-associated necrotizing enterocolitis (TANEC) in preterm infants. The aim of the manuscript was to systematically review studies reporting the effect of implementing a policy of withholding feeds on the incidence of TANEC in preterm infants. The following databases were searched for relevant studies published between the databases' inception and December 2016: PubMed, Embase, the Cochrane Central Register of Controlled Trials, the Cumulative Index of Nursing and Allied Health Literature, and Pediatric Academic Societies Abstract Archive. Other relevant sources were also searched. There were no restrictions on study design. Studies reporting on the incidence of TANEC (stage ≥2 necrotizing enterocolitis within 48-72 h) after implementation of a policy of withholding feeds in the peritransfusion period in preterm infants were included. This meta-analysis used a random-effects model with assessment of quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. There were no randomized controlled trials (RCTs). Pooled results from 7 non-RCTs (n = 7492) showed that withholding feeds during PRBC transfusion significantly reduced the incidence of TANEC (RR: 0.47; 95% CI: 0.28, 0.80; P = 0.005; I2 = 11%). The overall quality of evidence was moderate on GRADE analysis. These findings suggest that withholding feeds during the peritransfusion period may reduce the risk of TANEC in preterm infants. Adequately powered RCTs are needed to confirm these findings.
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:Caesarean-delivered preterm pigs were fed 3 d of parenteral nutrition followed by 2 d of enteral formula feeding. Antibiotics (n=11) or control saline (n=13) were given twice daily from birth to tissue collection at d 5. NEC-lesions and intestinal structure, function, microbiology and immunity markers were recorded. We used Affymetrix microarrays to investigate gene expression in intestinal tissues of preterm piglets treated with antibiotics or control saline. Twenty-four preterm piglets were delivered by caesarean section on day 105 of gestation from two healthy sows. All piglets were initially provided with parenteral nutrition via a vascular catheter, combined with small amounts of minimal enteral nutrition. On day three, all parenteral nutrition was stopped and total enteral nutrition was given through an oro-gastric feeding tube. Piglets were allocated into controls ( n=13) and an intervention group receiving oral and systemic broad-spectrum antibiotics ( n=11). To assure high systemic and intra luminal MIC values antibiotics were given both orally and intramuscularly. All antibiotics were given directly after feeding with an oral bolus and control pigs were given corresponding amounts of saline. On day five, all piglets were euthanized, and small intestinal tissue collected.