Talk:Gastrointestinal Tract - Postnatal
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Cite this page: Hill, M.A. (2026, October 7) Embryology Gastrointestinal Tract - Postnatal. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Gastrointestinal_Tract_-_Postnatal |
2011
Necrotizing enterocolitis: An update
Semin Fetal Neonatal Med. 2011 Apr 20. [Epub ahead of print] Berman L, Moss RL. Source Department of Surgery, Yale University School of Medicine, 333 Cedar Street, FMB 132, New Haven, CT 06520-8062, USA.
Abstract
Necrotizing enterocolitis (NEC) is a leading cause of death among patients in the neonatal intensive care unit, carrying a mortality rate of 15-30%. Its pathogenesis is multifactorial and involves an overreactive response of the immune system to an insult. This leads to increased intestinal permeability, bacterial translocation, and sepsis. There are many inflammatory mediators involved in this process, but thus far none has been shown to be a suitable target for preventive or therapeutic measures. NEC usually occurs in the second week of life after the initiation of enteral feeds, and the diagnosis is made based on physical examination findings, laboratory studies, and abdominal radiographs. Neonates with NEC are followed with serial abdominal examinations and radiographs, and may require surgery or primary peritoneal drainage for perforation or necrosis. Many survivors are plagued with long term complications including short bowel syndrome, abnormal growth, and neurodevelopmental delay. Several evidence-based strategies exist that may decrease the incidence of NEC including promotion of human breast milk feeding, careful feeding advancement, and prophylactic probiotic administration in at-risk patients. Prevention is likely to have the greatest impact on decreasing mortality and morbidity related to NEC, as little progress has been made with regard to improving outcomes for neonates once the disease process is underway.
Copyright © 2011. Published by Elsevier Ltd.
PMID: 21514258 http://www.ncbi.nlm.nih.gov/pubmed/21514258
Gram negative bacteria are associated with the early stages of necrotizing enterocolitis
PLoS One. 2011 Mar 22;6(3):e18084.
Carlisle EM, Poroyko V, Caplan MS, Alverdy JA, Liu D. Source Department of Surgery, University of Chicago Medical Center, Chicago, Illinois, United States of America.
Abstract
INTRODUCTION: Necrotizing enterocolitis (NEC) affects 5-10% of infants born weighing less than 1500 g. Most models of NEC recapitulate late-stage disease with gut necrosis and elevated inflammatory mediators. Evaluation of NEC at earlier, less lethal stages of disease will allow investigation of initial disease triggers and may advance our understanding of temporal relationships between factors implicated in NEC pathogenesis. In this manuscript, we describe our investigation of early NEC and test the hypothesis that bacteria and inflammatory mediators differ between animals with early NEC and disease free animals.
METHODS: On DOL7 C3HeB/FeJ pups were fed liquid formula with 1×10(4)Streptococcus thoraltensis, Serratia marcescens, and Pseudomonas aeruginosa every 3 h. To initiate NEC, pups underwent asphyxia (100% N(2) for 90 s) and hypothermia (4°C for 10 min) after feeding. Pups were euthanized at 72 h. Intestines were collected for histologic NEC scoring and DNA/RNA extraction. Bacterial populations were identified by 16S rRNA pyrosequencing and principal component analysis (PCA). RNA isolates underwent QRT-PCR for Toll-like Receptor 4 (TLR4) and inducible nitric oxide synthase (iNOS).
RESULTS: Despite histologic, intestinal damage in mice with NEC, no gross necrosis was observed suggesting early disease. QRT-PCR yielded no difference between groups in TLR4 or iNOS mRNA levels. PCA demonstrated relative clustering of microbial communities based on presence or absence of NEC. 16S pyrosequencing demonstrated similar phyla between groups (Firmicutes and Proteobacteria predominated in all animals). However, the colonic microbiota of animals with NEC had more Citrobacter (p<0.01), Klebsiella (p<0.05), and Tatumella (p<0.05), while that of animals without NEC had more Streptococcus (p<0.01) and Enterococcus (p<0.01).
CONCLUSION: Citrobacter, Klebsiella, and Tatumella are associated with NEC. Differential colonic bacteria were identified despite the lack of inflammatory mediator elevation traditionally associated with NEC. This suggests a temporal relationship between bacteria and inflammatory mediators such that alterations in gut microbiota are associated with early NEC, while inflammatory mediator elevation is associated with advanced NEC.
PMID: 21445365 http://www.ncbi.nlm.nih.gov/pubmed/21445365
Community analysis of bacteria colonizing intestinal tissue of neonates with necrotizing enterocolitis
BMC Microbiol. 2011 Apr 12;11(1):73. [Epub ahead of print]
Smith B, Bode S, Petersen BL, Jensen TK, Pipper C, Kloppenborg J, Boye M, Krogfelt KA, Molbak L.
ABSTRACT:
BACKGROUND: Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in newborn neonates. Bacteria are believed to be important in the pathogenesis of NEC but bacterial characterization has only been done on human faecal samples and experimental animal studies. The aim of this study was to investigate the microbial composition and the relative number of bacteria in inflamed intestinal tissue surgically removed from neonates diagnosed with NEC (n=24). The bacterial populations in the specimens were characterized by laser capture microdissection and subsequent sequencing combined with fluorescent in situ hybridization (FISH), using bacterial rRNA-targeting oligonucleotide probes.
RESULTS: Bacteria were detected in 22 of the 24 specimens, 71% had moderate to high densities of bacteria. The phyla detected by 16S rRNA gene sequencing were: Proteobacteria (49.0%), Firmicutes (30.4%), Actinobacteria (17.1%) and Bacteroidetes (3.6%). A major detected class of the phylum Proteobacteria belonged to gamma-proteobacteria. Surprisingly, Clostridium species were only detected in 4 of the specimens by FISH, but two of these specimens exhibited histological pneumatosis intestinalis and both specimens had a moderate to a high density of C. butyricum and C. parputrificum detected by using species specific FISH probes. A 16S rRNA gene sequence tag similar to Ralstonia species was detected in most of the neonatal tissues and members of this genus have been reported to be opportunistic pathogens but their role in NEC has still to be clarified.
CONCLUSION: In this study, in situ identification and community analysis of bacteria found in tissue specimens from neonates with NEC, were analysed for the first time. Although a large variability of bacteria was found in most of the analyzed specimens, no single or combination of known potential pathogenic bacteria species was dominating the samples suggestive NEC as non-infectious syndrome. However there was a significant correlation between the presence of C. butyricum & C. parputrificum and histological pneumatosis intestinalis. Finally this study emphasizes the possibility to examine the microbial composition directly on excised human tissues to avoid biases from faecal samples or culturing.
PMID: 21486476 http://www.ncbi.nlm.nih.gov/pubmed/21486476
http://www.biomedcentral.com/1471-2180/11/73
2010
Milk epidermal growth factor and gut protection
J Pediatr. 2010 Feb;156(2 Suppl):S31-5.
Dvorak B. Source Department of Pediatrics, University of Arizona, Tucson, AZ, USA. dvorakb@peds.arizona.edu
Abstract
Maternal milk is a complex fluid, with multifunctional roles within the developing gastrointestinal tract. Epidermal growth factor (EGF) and heparin-binding EGF-like growth factor (HB-EGF) are members of the family of EGF-related peptides. Biological actions of these growth factors are mediated via interaction with the EGF-receptor (EGF-R). In the early postnatal period, breast milk is the major source of EGF for the developing intestinal mucosa. HB-EGF is also detected in breast milk, but in concentrations 2 to 3 times lower than EGF. With normal physiological conditions, the intestinal epithelium undergoes a continuing process of cell proliferation, differentiation, and maturation. EGF plays an important role in these processes. In pathophysiologic situations, EGF contributes to epithelial protection from injury and post-injury mucosal repair. Necrotizing enterocolitis (NEC) is a devastating disease affecting infants born prematurely. The pathogenesis of NEC is not known, and there is no effective treatment for this disease. In an experimental NEC model, oral administration of a physiological dose of EGF significantly reduces the incidence and severity of NEC. HB-EGF provides similar protection against NEC, but only when pharmacological doses are used. Further studies are necessary before EGF can be introduced as an efficient therapeutic approach of intestinal injury.
Copyright 2010 Mosby, Inc. All rights reserved.
PMID: 20105663 http://www.ncbi.nlm.nih.gov/pubmed/20105663
